Merge remote-tracking branch 'origin/main'

# Conflicts:
#	README.md

CHANGELOG.md

@@ -0,0 +1,54 @@
+# Changelog
+
+All notable changes to floret-kit are documented here. The format follows
+[Keep a Changelog](https://keepachangelog.com/).
+
+floret-kit is consumed **from source** — each app embeds it as a git submodule
+and builds it through a Gradle composite build, pinning a specific commit. There
+are no binary releases; "version" tracks the shared `version` in the root build
+(currently `0.1.0`). Entries are grouped by module.
+
+## [Unreleased]
+
+### Added
+
+- **`core-time`** (JVM library) — pure-Kotlin date/time helpers, no Android and
+  no third-party dependencies:
+  - `DayWindow.today()` — local-day boundaries for smart-list logic.
+  - `Instant.formatDate()` / `formatTime()` / `formatDateTime()` — locale- and
+    zone-aware display formatting over `kotlin.time.Instant`.
+  - `TimeBridge` — `Long` epoch-millis ↔ `Instant`, for content-provider I/O.
+- **`core-crash`** (Android library) — privacy-respecting, on-device crash
+  capture and reporting. Writes an allowlist-only report (app/Android/device
+  version, locale, time, stack trace — nothing else) to private storage and
+  chains to the platform handler; uploads nothing. Includes startup crash-loop
+  detection, a report dialog that shows the full text before it leaves the
+  device, and an issue-tracker hand-off. Per-app specifics (display name, issue
+  URLs) come from a `CrashConfig` supplied at `install()`; each app keeps its
+  own thin themed `CrashReportActivity`.
+- **`identity`** (Android library) — the family's Material 3 Expressive theme
+  factory `FloretExpressiveTheme(lightScheme, darkScheme, …)` (dynamic colour on
+  API 31+, system light/dark fallback, the standard motion scheme) plus
+  `rememberNavSlideSpec()`. Each app passes its own seed-derived colour schemes
+  and typography — the mechanics are shared, the look is not.
+- **`components`** (Android library) — the shared Compose component vocabulary:
+  - `GroupedSurface` / `GroupedRow` + `Position` / `positionOf` — the canonical
+    press-morphing tonal grouped-row primitive (the Android-15 settings pattern).
+  - `InlineTextField` — the borderless tonal text input (capitalization is a
+    parameter).
+  - `OptionCard` — the sanctioned selection-dialog pick.
+  - `CollapsingScaffold` — the collapsing settings/sub-screen scaffold.
+  - `FullScreenPicker` / `OptionPicker` — the full-screen single-select picker.
+  - `pastelize()` — softens a raw provider colour to a theme-fitting pastel.
+
+  App-agnostic by design: apps compose their own screens and keep their own
+  identity chips/icons. String resources here (e.g. `back`) are fallbacks an app
+  can override.
+
+### Conventions
+
+- **No `foojay` toolchain resolver** anywhere — it can fetch a JDK at build time,
+  which reproducible / official F-Droid builds reject. Modules set `jvmTarget`
+  directly. See [`docs/ARCHITECTURE.md`](docs/ARCHITECTURE.md).
+- AGP 9.x provides built-in Kotlin compilation, so Android modules apply only the
+  Android library + Compose plugins (no separate `kotlin.android`).

CONTRIBUTING.md

@@ -0,0 +1,77 @@
+# Contributing to floret-kit
+
+floret-kit is the shared Material 3 Expressive design system + plumbing for the
+Floret app family. Before changing it, skim
+[`docs/ARCHITECTURE.md`](docs/ARCHITECTURE.md) (how it's built and consumed) and
+[`docs/ROADMAP.md`](docs/ROADMAP.md) (what's in scope). This file is the
+practical how.
+
+## The rules
+
+1. **Share mechanics, not look.** Extract the machinery; leave seed colours,
+   palettes, identity chips, and wording to the apps. If a piece can't be made
+   app-agnostic without contortion, it doesn't belong here yet.
+2. **No app coupling.** A kit module never imports an app package, an app's `R`,
+   or a domain type. App-specific values arrive as **constructor/config
+   parameters** or **callbacks** (see `core-crash`'s `CrashConfig`,
+   `InlineTextField`'s `capitalization`).
+3. **String resources are fallbacks.** Kit strings are English defaults an app
+   overrides via resource merge. Don't put app-specific or per-app-divergent
+   wording in the kit.
+4. **Bake divergence into parameters, don't pick a silent winner.** Where two
+   apps differ, expose the difference. When a shared primitive adopts one app's
+   version as canonical, that's a deliberate, documented convergence.
+5. **No `foojay` toolchain resolver** — not in any `*.gradle.kts`, not even as a
+   token in a comment. It breaks reproducible / official F-Droid builds. Set
+   `jvmTarget` directly. See [`docs/ARCHITECTURE.md`](docs/ARCHITECTURE.md) §5.
+
+## Prerequisites
+
+- JDK 17
+- Android SDK (compileSdk 37) for the Android modules — set `ANDROID_HOME` or add
+  a gitignored `local.properties` with `sdk.dir`. Pure-JVM modules need neither.
+
+## Build & test
+
+```sh
+./gradlew :core-time:test              # JVM module (JUnit 5 + Truth)
+./gradlew :core-crash:testDebugUnitTest
+./gradlew :identity:assembleDebug
+./gradlew build                        # everything
+```
+
+In practice the kit is exercised through a consuming app's composite build (e.g.
+`agendula`'s `./gradlew assembleDebug`), which compiles the included modules from
+source.
+
+## Adding a module
+
+1. Create `:<module>` and add `include(":<module>")` to
+   [`settings.gradle.kts`](settings.gradle.kts).
+2. Add a `<module>/build.gradle.kts`:
+   - **JVM:** `plugins { alias(libs.plugins.kotlin.jvm) }`, a `kotlin { compilerOptions { jvmTarget = JVM_17 } }` block, JUnit 5 test deps.
+   - **Android:** `plugins { alias(libs.plugins.android.library); alias(libs.plugins.kotlin.compose) }` (no `kotlin.android` — AGP 9.x is built-in), `namespace = "de.jeanlucmakiola.floret.<area>"`, `compileSdk 37` / `minSdk 29`, `jvmTarget = JVM_17`.
+3. Put sources under `src/main/kotlin/de/jeanlucmakiola/floret/<area>/`. The root
+   build's `subprojects {}` sets the shared `group`/`version`, so no per-module
+   coordinates are needed.
+4. Add an entry to [`CHANGELOG.md`](CHANGELOG.md), the README module table, and
+   (if status-worthy) [`docs/ROADMAP.md`](docs/ROADMAP.md).
+
+## Adopting the kit in an app
+
+1. `git submodule add <kit-url> floret-kit`.
+2. `includeBuild("floret-kit")` in the app's `settings.gradle.kts`.
+3. `implementation("de.jeanlucmakiola.floret:<module>")` in the app module.
+4. Ensure CI checks out submodules (`submodules: recursive`) and the included
+   build can find the SDK (`ANDROID_HOME`). For official F-Droid reproducible
+   builds, add `submodules: true` to the fdroiddata recipe and have the repro
+   guard scan the submodule.
+5. The app pins a kit commit via the submodule; bump it deliberately to adopt kit
+   changes.
+
+## Validate before pushing
+
+- `python3 -c "import yaml; yaml.safe_load(open('<workflow>.yml'))"` after any
+  workflow edit — indentation bites.
+- A consuming app's `lintDebug` + `testDebugUnitTest` + `assembleDebug` should be
+  green after a kit change you mean to land.

LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2026 Jean-Luc Makiola
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

@@ -25,18 +25,38 @@ implementation("de.jeanlucmakiola.floret:core-time")
 ```
 
 Gradle's dependency substitution maps `de.jeanlucmakiola.floret:<module>` to the
-local source module — edit the kit and the app picks it up immediately.
+local source module — edit the kit and the app picks it up immediately. Android
+modules need an SDK location for the included build: set `ANDROID_HOME` (CI) or
+add a gitignored `<app>/floret-kit/local.properties` with `sdk.dir` (locally).
+See [`docs/ARCHITECTURE.md`](docs/ARCHITECTURE.md) for the full consumption model.
 
 ## Modules
 
-| Module | What it holds |
-|--------|---------------|
-| `core-time` | Pure-Kotlin date/time helpers: local-day windows (`DayWindow`) for smart-list logic and locale/zone-aware display formatting (`Instant.formatDate()` / `formatTime()` / `formatDateTime()`). No Android, no deps. |
+| Module | Type | What it holds |
+|--------|------|---------------|
+| `core-time` | JVM | Date/time helpers: `DayWindow` local-day windows, locale/zone-aware `Instant` formatting, `TimeBridge` (millis ↔ `Instant`). No Android, no deps. |
+| `core-reminders` | JVM | Reminder-lead plumbing: the lead-time unit model (`ReminderUnit`, `decomposeReminderMinutes`), the per-target override model (`ReminderOverride` + `reminderLeadFor` / `applyReminderOverride`) and the stored-format codec (`ReminderOverrideCodec`, separators configurable per app). Each app layers its own DataStore + string labels on top. |
+| `core-locale` | Android | Per-app language plumbing (`AppLanguage`): read the shipped languages from the app's `res/xml/locales_config.xml`, get/set the applied language via `AppCompatDelegate`, render each language's autonym. The app passes its own `locales_config`; appcompat only, no Compose. |
+| `core-crash` | Android | Privacy-respecting on-device crash capture + report dialog + issue-tracker hand-off. Parameterized per app via `CrashConfig`. |
+| `identity` | Android | The M3 Expressive theme factory `FloretExpressiveTheme(…)`, `rememberNavSlideSpec()`, the content transitions (`expandEnter`/`collapseExit`/`itemEnter`/…) and the `predictiveBack` peek. Each app supplies its own seed/palette. |
+| `components` | Android | Shared Compose vocabulary + recipes: `GroupedSurface`/`GroupedRow`, `InlineTextField`, `OptionCard`, `CollapsingScaffold`, `OptionPicker`, `pastelize()`, `DialogControls`, `OnboardingScaffold`, `OptionalFormSection`, `AboutCard`, `LanguagePickerRow`. |
 
-_More modules (identity/theme, components, screen recipes, provider/prefs/reminders/crash plumbing) land as they're extracted from the apps._
+_The principle: the **mechanics** are shared, the **look** stays per-app. See
+[`docs/ROADMAP.md`](docs/ROADMAP.md) for what's extracted, deferred, and
+deliberately not shared._
+
+## Docs
+
+See [`docs/`](docs/) — start with [`docs/README.md`](docs/README.md)
+([ARCHITECTURE](docs/ARCHITECTURE.md), [ROADMAP](docs/ROADMAP.md)) and
+[`CONTRIBUTING.md`](CONTRIBUTING.md) to add or change a module.
+[`CHANGELOG.md`](CHANGELOG.md) tracks what landed.
+>>>>>>> origin/main
 
 ## Build
 
 ```sh
-./gradlew :core-time:test
+./gradlew :core-time:test          # JVM module tests
+./gradlew :core-crash:testDebugUnitTest
+./gradlew build                    # everything (Android modules need an SDK; see above)
 ```

components/build.gradle.kts

@@ -33,6 +33,12 @@ kotlin {
 }
 
 dependencies {
+    // identity supplies the shared motion (expandEnter/collapseExit) that the
+    // revealable components animate with.
+    implementation(project(":identity"))
+    // core-locale backs the language-picker recipe (AppLanguage).
+    implementation(project(":core-locale"))
+
     implementation(platform(libs.androidx.compose.bom))
     implementation(libs.androidx.ui)
     implementation(libs.androidx.foundation)

components/src/main/kotlin/de/jeanlucmakiola/floret/components/DialogControls.kt

@@ -0,0 +1,95 @@
+package de.jeanlucmakiola.floret.components
+
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.ArrowDropDown
+import androidx.compose.material3.DropdownMenu
+import androidx.compose.material3.DropdownMenuItem
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.text.input.KeyboardType
+import androidx.compose.ui.unit.dp
+
+/**
+ * Tonal 3-digit number input shared by the custom reminder/recurrence steps and
+ * the pickers — the family's [InlineTextField] over a tonal surface, so it
+ * matches the card/grouped-row design language (not Material's outlined field).
+ * Non-digit input and anything past three digits is ignored.
+ */
+@Composable
+fun DialogAmountField(
+    value: String,
+    onValueChange: (String) -> Unit,
+    placeholder: String,
+) {
+    // surfaceContainerHighest — the picker/dialog sits on surfaceContainerHigh,
+    // so anything lower vanishes.
+    Surface(
+        color = MaterialTheme.colorScheme.surfaceContainerHighest,
+        shape = RoundedCornerShape(12.dp),
+    ) {
+        InlineTextField(
+            value = value,
+            onValueChange = { text ->
+                if (text.length <= 3 && text.all(Char::isDigit)) onValueChange(text)
+            },
+            placeholder = placeholder,
+            textStyle = MaterialTheme.typography.titleMedium,
+            keyboardType = KeyboardType.Number,
+            modifier = Modifier
+                .width(72.dp)
+                .padding(horizontal = 14.dp, vertical = 12.dp),
+        )
+    }
+}
+
+/** Tonal dropdown trigger + menu shared by the custom reminder/recurrence steps and pickers. */
+@Composable
+fun DialogUnitDropdown(
+    label: String,
+    entries: List<String>,
+    onPick: (Int) -> Unit,
+) {
+    var open by remember { mutableStateOf(false) }
+    Box {
+        Surface(
+            color = MaterialTheme.colorScheme.surfaceContainerHighest,
+            shape = RoundedCornerShape(12.dp),
+            onClick = { open = true },
+        ) {
+            Row(
+                verticalAlignment = Alignment.CenterVertically,
+                modifier = Modifier.padding(start = 14.dp, end = 8.dp, top = 12.dp, bottom = 12.dp),
+            ) {
+                Text(text = label, style = MaterialTheme.typography.titleMedium)
+                Spacer(Modifier.width(4.dp))
+                Icon(imageVector = Icons.Default.ArrowDropDown, contentDescription = null)
+            }
+        }
+        DropdownMenu(expanded = open, onDismissRequest = { open = false }) {
+            entries.forEachIndexed { index, entry ->
+                DropdownMenuItem(
+                    text = { Text(entry) },
+                    onClick = {
+                        onPick(index)
+                        open = false
+                    },
+                )
+            }
+        }
+    }
+}

components/src/main/kotlin/de/jeanlucmakiola/floret/components/FormSection.kt

@@ -0,0 +1,26 @@
+package de.jeanlucmakiola.floret.components
+
+import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.ColumnScope
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import de.jeanlucmakiola.floret.identity.collapseExit
+import de.jeanlucmakiola.floret.identity.expandEnter
+
+/**
+ * A form section that reveals/hides with the family's expand+fade motion — the
+ * shared wrapper for the optional fields behind a "More fields" toggle in the
+ * edit forms. [content] is laid out in a full-width [Column].
+ */
+@Composable
+fun OptionalFormSection(visible: Boolean, content: @Composable ColumnScope.() -> Unit) {
+    AnimatedVisibility(
+        visible = visible,
+        enter = expandEnter(),
+        exit = collapseExit(),
+    ) {
+        Column(modifier = Modifier.fillMaxWidth(), content = content)
+    }
+}

components/src/main/kotlin/de/jeanlucmakiola/floret/components/Onboarding.kt

@@ -0,0 +1,117 @@
+package de.jeanlucmakiola.floret.components
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.ColumnScope
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.navigationBarsPadding
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Scaffold
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.unit.dp
+
+/** MD3 8dp spacing scale shared by the onboarding screens. */
+object OnboardingSpace {
+    val xs = 8.dp
+    val sm = 16.dp
+    val md = 24.dp
+    val lg = 32.dp
+    val xl = 48.dp
+}
+
+/**
+ * Shared onboarding shell: a scrollable, centred [hero] + [body] with the
+ * call(s) to action ([actions]) pinned to the bottom (clear of the navigation
+ * bar). The content slot is centred horizontally; benefit rows fill the width so
+ * their own content left-aligns. Each app supplies its own hero so the apps read
+ * as one family while keeping their own mark.
+ */
+@Composable
+fun OnboardingScaffold(
+    hero: @Composable () -> Unit,
+    actions: @Composable ColumnScope.() -> Unit,
+    modifier: Modifier = Modifier,
+    body: @Composable ColumnScope.() -> Unit,
+) {
+    Scaffold(
+        modifier = modifier,
+        containerColor = MaterialTheme.colorScheme.surface,
+        bottomBar = {
+            Column(
+                modifier = Modifier
+                    .fillMaxWidth()
+                    .navigationBarsPadding()
+                    .padding(horizontal = OnboardingSpace.md, vertical = OnboardingSpace.sm),
+                horizontalAlignment = Alignment.CenterHorizontally,
+                verticalArrangement = Arrangement.spacedBy(4.dp),
+                content = actions,
+            )
+        },
+    ) { innerPadding ->
+        Column(
+            modifier = Modifier
+                .fillMaxSize()
+                .padding(innerPadding)
+                .verticalScroll(rememberScrollState())
+                .padding(horizontal = OnboardingSpace.md),
+            horizontalAlignment = Alignment.CenterHorizontally,
+        ) {
+            Spacer(Modifier.height(OnboardingSpace.xl))
+            hero()
+            Spacer(Modifier.height(OnboardingSpace.lg))
+            body()
+            Spacer(Modifier.height(OnboardingSpace.md))
+        }
+    }
+}
+
+/** One trust point: a tonal icon chip on the left, title + supporting text right. */
+@Composable
+fun BenefitRow(icon: ImageVector, title: String, body: String) {
+    Row(
+        modifier = Modifier.fillMaxWidth(),
+        verticalAlignment = Alignment.CenterVertically,
+    ) {
+        Box(
+            modifier = Modifier
+                .size(44.dp)
+                .clip(CircleShape)
+                .background(MaterialTheme.colorScheme.secondaryContainer),
+            contentAlignment = Alignment.Center,
+        ) {
+            Icon(
+                imageVector = icon,
+                contentDescription = null,
+                tint = MaterialTheme.colorScheme.onSecondaryContainer,
+                modifier = Modifier.size(22.dp),
+            )
+        }
+        Spacer(Modifier.width(OnboardingSpace.sm))
+        Column(modifier = Modifier.weight(1f)) {
+            Text(text = title, style = MaterialTheme.typography.titleMedium)
+            Text(
+                text = body,
+                style = MaterialTheme.typography.bodyMedium,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+            )
+        }
+    }
+}

components/src/main/kotlin/de/jeanlucmakiola/floret/components/SettingsRecipes.kt

@@ -0,0 +1,147 @@
+package de.jeanlucmakiola.floret.components
+
+import android.content.Intent
+import android.net.Uri
+import androidx.annotation.XmlRes
+import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.PaddingValues
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material3.FilledTonalButton
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.OutlinedButton
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.unit.dp
+import de.jeanlucmakiola.floret.locale.AppLanguage
+
+/** A labelled, icon-led external link rendered as a button in [AboutCard]. */
+data class AboutLink(val icon: ImageVector, val label: String, val url: String)
+
+/**
+ * The "about this app" card shared across the family: the app's [logo] beside
+ * its [appName] and [author], then [primaryLinks] as a row of equal-width
+ * outlined buttons (e.g. source, licence) and an optional full-width
+ * [highlightLink] tonal button (e.g. donate). Each link opens its URL in the
+ * browser. The app supplies its own logo, strings and links.
+ */
+@Composable
+fun AboutCard(
+    logo: @Composable () -> Unit,
+    appName: String,
+    author: String,
+    primaryLinks: List<AboutLink>,
+    highlightLink: AboutLink? = null,
+) {
+    val context = LocalContext.current
+    val open = { url: String ->
+        runCatching { context.startActivity(Intent(Intent.ACTION_VIEW, Uri.parse(url))) }
+        Unit
+    }
+    Surface(
+        color = MaterialTheme.colorScheme.surfaceContainerHigh,
+        shape = RoundedCornerShape(24.dp),
+        modifier = Modifier.fillMaxWidth(),
+    ) {
+        Column(Modifier.fillMaxWidth().padding(16.dp)) {
+            Row(verticalAlignment = Alignment.CenterVertically) {
+                logo()
+                Spacer(Modifier.width(16.dp))
+                Column(Modifier.weight(1f)) {
+                    Text(appName, style = MaterialTheme.typography.titleLarge)
+                    Text(
+                        text = author,
+                        style = MaterialTheme.typography.bodyMedium,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant,
+                    )
+                }
+            }
+            if (primaryLinks.isNotEmpty()) {
+                Spacer(Modifier.height(12.dp))
+                Row(Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+                    primaryLinks.forEach { link ->
+                        OutlinedButton(
+                            onClick = { open(link.url) },
+                            contentPadding = PaddingValues(horizontal = 12.dp),
+                            modifier = Modifier.weight(1f),
+                        ) {
+                            Icon(link.icon, contentDescription = null, modifier = Modifier.size(18.dp))
+                            Spacer(Modifier.width(8.dp))
+                            Text(link.label)
+                        }
+                    }
+                }
+            }
+            if (highlightLink != null) {
+                Spacer(Modifier.height(8.dp))
+                FilledTonalButton(onClick = { open(highlightLink.url) }, modifier = Modifier.fillMaxWidth()) {
+                    Icon(highlightLink.icon, contentDescription = null, modifier = Modifier.size(18.dp))
+                    Spacer(Modifier.width(8.dp))
+                    Text(highlightLink.label)
+                }
+            }
+        }
+    }
+}
+
+/**
+ * A settings row that opens a full-screen language picker, backed by
+ * [AppLanguage]. The choice is mirrored locally so the row updates instantly
+ * before the activity recreation lands. [autoLabel] names the follow-the-system
+ * option (the `null` tag); [localesConfig] is the app's `res/xml/locales_config`;
+ * [leading] is the row's icon.
+ */
+@Composable
+fun LanguagePickerRow(
+    position: Position,
+    title: String,
+    autoLabel: String,
+    @XmlRes localesConfig: Int,
+    leading: @Composable () -> Unit,
+) {
+    val context = LocalContext.current
+    var current by remember { mutableStateOf(AppLanguage.currentTag()) }
+    var showDialog by remember { mutableStateOf(false) }
+    // null = follow the system; the rest are BCP-47 tags from locales_config.xml.
+    val options = remember { listOf<String?>(null) + AppLanguage.supportedTags(context, localesConfig) }
+    val label: (String?) -> String = { tag -> tag?.let { AppLanguage.displayName(it) } ?: autoLabel }
+
+    GroupedRow(
+        title = title,
+        summary = label(current),
+        position = position,
+        leading = leading,
+        onClick = { showDialog = true },
+    )
+
+    if (showDialog) {
+        OptionPicker(
+            title = title,
+            options = options,
+            selected = current,
+            label = { label(it) },
+            onSelect = {
+                current = it
+                AppLanguage.apply(it)
+            },
+            onDismiss = { showDialog = false },
+        )
+    }
+}

core-locale/build.gradle.kts

@@ -0,0 +1,46 @@
+// core-locale — per-app language plumbing shared across the family: read the
+// shipped languages from res/xml/locales_config.xml, get/set the applied
+// language via AppCompatDelegate, and render each language's autonym. App-
+// agnostic — the consuming app passes its own locales_config resource id; no
+// Compose, no DataStore.
+plugins {
+    alias(libs.plugins.android.library)
+}
+
+android {
+    namespace = "de.jeanlucmakiola.floret.locale"
+    compileSdk = 37
+
+    defaultConfig {
+        minSdk = 29
+    }
+
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_17
+        targetCompatibility = JavaVersion.VERSION_17
+    }
+
+    testOptions {
+        unitTests {
+            all { it.useJUnitPlatform() }
+            isReturnDefaultValues = true
+        }
+    }
+}
+
+kotlin {
+    compilerOptions {
+        jvmTarget = org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_17
+    }
+}
+
+dependencies {
+    // appcompat brings AppCompatDelegate plus its core (LocaleListCompat) and
+    // annotation (XmlRes) transitives.
+    implementation(libs.androidx.appcompat)
+
+    testImplementation(libs.junit.jupiter.api)
+    testRuntimeOnly(libs.junit.jupiter.engine)
+    testRuntimeOnly(libs.junit.platform.launcher)
+    testImplementation(libs.truth)
+}

core-locale/src/main/kotlin/de/jeanlucmakiola/floret/locale/AppLanguage.kt

@@ -0,0 +1,80 @@
+package de.jeanlucmakiola.floret.locale
+
+import android.content.Context
+import androidx.annotation.XmlRes
+import androidx.appcompat.app.AppCompatDelegate
+import androidx.core.os.LocaleListCompat
+import org.xmlpull.v1.XmlPullParser
+import java.util.Locale
+
+private const val ANDROID_NS = "http://schemas.android.com/apk/res/android"
+
+/**
+ * Per-app language via AppCompatDelegate, driven by an app's
+ * res/xml/locales_config.xml.
+ *
+ * That file is the single source of truth for which languages an app ships:
+ * dropping in a values-<tag> translation and adding a matching `<locale>` entry
+ * makes the language show up here and in the system per-app-language settings,
+ * with no other code change. The system-default choice is represented as `null`.
+ *
+ * On API 33+ this delegates to the platform per-app-languages API; below that
+ * the appcompat backport persists the choice itself (manifest `autoStoreLocales`
+ * service), so we don't mirror it in DataStore. Setting a locale recreates the
+ * activity, which re-reads the current value for the picker.
+ */
+object AppLanguage {
+
+    /**
+     * The BCP-47 tags the app ships translations for, in declaration order, as
+     * listed in [localesConfig] (the app's `res/xml/locales_config.xml`). Returns
+     * whatever could be parsed; a missing or malformed config yields an empty
+     * list (the picker then offers only the system-default entry rather than
+     * crashing).
+     */
+    fun supportedTags(context: Context, @XmlRes localesConfig: Int): List<String> {
+        val tags = mutableListOf<String>()
+        val parser = context.resources.getXml(localesConfig)
+        try {
+            var event = parser.eventType
+            while (event != XmlPullParser.END_DOCUMENT) {
+                if (event == XmlPullParser.START_TAG && parser.name == "locale") {
+                    parser.getAttributeValue(ANDROID_NS, "name")?.let(tags::add)
+                }
+                event = parser.next()
+            }
+        } catch (_: Exception) {
+            // Fall back to whatever was parsed before the failure.
+        } finally {
+            parser.close()
+        }
+        return tags
+    }
+
+    /** The applied app language as a BCP-47 tag, or `null` when following the system. */
+    fun currentTag(): String? {
+        val locales = AppCompatDelegate.getApplicationLocales()
+        return if (locales.isEmpty) null else locales[0]?.toLanguageTag()
+    }
+
+    /** Apply a BCP-47 tag, or `null` to follow the system languages. */
+    fun apply(tag: String?) {
+        val locales = if (tag == null) {
+            LocaleListCompat.getEmptyLocaleList()
+        } else {
+            LocaleListCompat.forLanguageTags(tag)
+        }
+        AppCompatDelegate.setApplicationLocales(locales)
+    }
+
+    /**
+     * The autonym for a tag — the language's own name in its own script, e.g.
+     * "Deutsch", "English", "Français" — so users find their language regardless
+     * of the current UI language. Capitalised per the language's own rules.
+     */
+    fun displayName(tag: String): String {
+        val locale = Locale.forLanguageTag(tag)
+        return locale.getDisplayName(locale)
+            .replaceFirstChar { if (it.isLowerCase()) it.titlecase(locale) else it.toString() }
+    }
+}

core-locale/src/test/kotlin/de/jeanlucmakiola/floret/locale/AppLanguageTest.kt

@@ -0,0 +1,20 @@
+package de.jeanlucmakiola.floret.locale
+
+import com.google.common.truth.Truth.assertThat
+import org.junit.jupiter.api.Test
+
+class AppLanguageTest {
+
+    @Test
+    fun `autonym is the language's own name`() {
+        assertThat(AppLanguage.displayName("en")).isEqualTo("English")
+        assertThat(AppLanguage.displayName("de")).isEqualTo("Deutsch")
+    }
+
+    @Test
+    fun `autonym is capitalised per the language's own rules`() {
+        // French autonyms are lower-case in CLDR ("français"); the picker shows
+        // them title-cased so each language reads as a proper name.
+        assertThat(AppLanguage.displayName("fr")).isEqualTo("Français")
+    }
+}

core-reminders/build.gradle.kts

@@ -0,0 +1,32 @@
+// core-reminders — pure-Kotlin reminder-lead plumbing shared across the family:
+// the lead-time unit model (ReminderUnit / decomposeReminderMinutes), the
+// per-target override model (ReminderOverride + resolution helpers) and the
+// stored-format codec (ReminderOverrideCodec, separators configurable so each
+// app keeps its on-disk format). No Android, no third-party deps — a plain JVM
+// library, like core-time; each app layers its own DataStore + string labels on
+// top.
+plugins {
+    alias(libs.plugins.kotlin.jvm)
+}
+
+java {
+    sourceCompatibility = JavaVersion.VERSION_17
+    targetCompatibility = JavaVersion.VERSION_17
+}
+
+kotlin {
+    compilerOptions {
+        jvmTarget = org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_17
+    }
+}
+
+dependencies {
+    testImplementation(libs.junit.jupiter.api)
+    testRuntimeOnly(libs.junit.jupiter.engine)
+    testRuntimeOnly(libs.junit.platform.launcher)
+    testImplementation(libs.truth)
+}
+
+tasks.test {
+    useJUnitPlatform()
+}

core-reminders/src/main/kotlin/de/jeanlucmakiola/floret/reminders/ReminderOverride.kt

@@ -0,0 +1,44 @@
+package de.jeanlucmakiola.floret.reminders
+
+/**
+ * A target's override of the default reminder lead time — a list (Agendula) or a
+ * calendar (Calendula). Targets are keyed by id in the override map; this is the
+ * choice a picker returns.
+ */
+sealed interface ReminderOverride {
+    /** No override — the target uses the global default. */
+    data object Inherit : ReminderOverride
+
+    /** Explicit "no reminder" for this target, regardless of the global default. */
+    data object None : ReminderOverride
+
+    /** A specific lead time in minutes before due. */
+    data class Minutes(val minutes: Int) : ReminderOverride
+}
+
+/**
+ * The lead time for [id]: its override if one is set (a null map value means an
+ * explicit "no reminder"), otherwise the global [default]. A null result means
+ * no reminder. Mirrors the absent/null/value semantics of the override map.
+ */
+fun Map<Long, Int?>.reminderLeadFor(id: Long, default: Int): Int? =
+    if (containsKey(id)) this[id] else default
+
+/**
+ * Read [id]'s entry as a [ReminderOverride]: absent → [Inherit], null → [None],
+ * a value → [Minutes].
+ */
+fun Map<Long, Int?>.reminderOverrideFor(id: Long): ReminderOverride = when {
+    !containsKey(id) -> ReminderOverride.Inherit
+    this[id] == null -> ReminderOverride.None
+    else -> ReminderOverride.Minutes(getValue(id)!!)
+}
+
+/** Apply [override] for [id] to this override map ([Inherit] removes the key). */
+fun MutableMap<Long, Int?>.applyReminderOverride(id: Long, override: ReminderOverride) {
+    when (override) {
+        ReminderOverride.Inherit -> remove(id)
+        ReminderOverride.None -> put(id, null)
+        is ReminderOverride.Minutes -> put(id, override.minutes)
+    }
+}

core-reminders/src/main/kotlin/de/jeanlucmakiola/floret/reminders/ReminderOverrideCodec.kt

@@ -0,0 +1,38 @@
+package de.jeanlucmakiola.floret.reminders
+
+/**
+ * Encodes a per-target reminder-override map (`id → minutes`, where a null value
+ * is an explicit "no reminder") to and from a single stored string, e.g.
+ * `"12:30;7:none"`.
+ *
+ * The separators are configurable because each app already has bytes on disk in
+ * its own dialect — Agendula stores `id:minutes`, Calendula `id=minutes` — and
+ * the stored format must stay stable. Use [DEFAULT] (Agendula's `:` / `;`) or
+ * build a codec with the app's own separators; never change an app's separators
+ * after release without a migration.
+ */
+class ReminderOverrideCodec(
+    private val entrySep: String = ";",
+    private val keyValueSep: String = ":",
+    private val noneToken: String = "none",
+) {
+    /** Decode the stored string into a map (a null value = explicit no-reminder). */
+    fun parse(stored: String?): Map<Long, Int?> {
+        if (stored.isNullOrBlank()) return emptyMap()
+        return stored.split(entrySep).mapNotNull { entry ->
+            val parts = entry.split(keyValueSep).takeIf { it.size == 2 } ?: return@mapNotNull null
+            val id = parts[0].toLongOrNull() ?: return@mapNotNull null
+            val value = if (parts[1] == noneToken) null else parts[1].toIntOrNull() ?: return@mapNotNull null
+            id to value
+        }.toMap()
+    }
+
+    /** Encode the map back to its stored string form. */
+    fun serialize(map: Map<Long, Int?>): String =
+        map.entries.joinToString(entrySep) { (id, minutes) -> "$id$keyValueSep${minutes ?: noneToken}" }
+
+    companion object {
+        /** Agendula's dialect: `id:minutes` entries joined by `;`. */
+        val DEFAULT = ReminderOverrideCodec()
+    }
+}

core-reminders/src/main/kotlin/de/jeanlucmakiola/floret/reminders/ReminderUnit.kt

@@ -0,0 +1,31 @@
+package de.jeanlucmakiola.floret.reminders
+
+/** The unit of a custom reminder lead time; [minutesFactor] converts to minutes. */
+enum class ReminderUnit(val minutesFactor: Int) {
+    Minutes(1),
+    Hours(60),
+    Days(1_440),
+    Weeks(10_080),
+}
+
+/**
+ * A reminder lead time broken into a whole [amount] of a [unit] — the seed for a
+ * custom-amount editor. [amount] is null when there is no lead time to show.
+ */
+data class ReminderAmount(val amount: Int?, val unit: ReminderUnit)
+
+/**
+ * Decompose a reminder lead time (minutes before due) into the largest unit that
+ * divides it evenly: 120 → 2 hours, 1 440 → 1 day, 10 080 → 1 week, 90 → 90
+ * minutes. null or a non-positive lead time → no amount, defaulting to minutes.
+ */
+fun decomposeReminderMinutes(minutes: Int?): ReminderAmount = when {
+    minutes == null || minutes <= 0 -> ReminderAmount(null, ReminderUnit.Minutes)
+    minutes % ReminderUnit.Weeks.minutesFactor == 0 ->
+        ReminderAmount(minutes / ReminderUnit.Weeks.minutesFactor, ReminderUnit.Weeks)
+    minutes % ReminderUnit.Days.minutesFactor == 0 ->
+        ReminderAmount(minutes / ReminderUnit.Days.minutesFactor, ReminderUnit.Days)
+    minutes % ReminderUnit.Hours.minutesFactor == 0 ->
+        ReminderAmount(minutes / ReminderUnit.Hours.minutesFactor, ReminderUnit.Hours)
+    else -> ReminderAmount(minutes, ReminderUnit.Minutes)
+}

core-reminders/src/test/kotlin/de/jeanlucmakiola/floret/reminders/ReminderModelTest.kt

@@ -0,0 +1,52 @@
+package de.jeanlucmakiola.floret.reminders
+
+import com.google.common.truth.Truth.assertThat
+import org.junit.jupiter.api.Test
+
+class ReminderModelTest {
+
+    @Test
+    fun `decompose picks the largest whole unit`() {
+        assertThat(decomposeReminderMinutes(120)).isEqualTo(ReminderAmount(2, ReminderUnit.Hours))
+        assertThat(decomposeReminderMinutes(1_440)).isEqualTo(ReminderAmount(1, ReminderUnit.Days))
+        assertThat(decomposeReminderMinutes(10_080)).isEqualTo(ReminderAmount(1, ReminderUnit.Weeks))
+        assertThat(decomposeReminderMinutes(90)).isEqualTo(ReminderAmount(90, ReminderUnit.Minutes))
+    }
+
+    @Test
+    fun `decompose of null or non-positive has no amount`() {
+        assertThat(decomposeReminderMinutes(null)).isEqualTo(ReminderAmount(null, ReminderUnit.Minutes))
+        assertThat(decomposeReminderMinutes(0)).isEqualTo(ReminderAmount(null, ReminderUnit.Minutes))
+        assertThat(decomposeReminderMinutes(-5)).isEqualTo(ReminderAmount(null, ReminderUnit.Minutes))
+    }
+
+    @Test
+    fun `reminderLeadFor distinguishes absent, explicit-none and a value`() {
+        val map = mapOf(1L to 30, 2L to null)
+        assertThat(map.reminderLeadFor(1L, default = 10)).isEqualTo(30)
+        assertThat(map.reminderLeadFor(2L, default = 10)).isNull() // explicit no-reminder
+        assertThat(map.reminderLeadFor(3L, default = 10)).isEqualTo(10) // inherits default
+    }
+
+    @Test
+    fun `reminderOverrideFor maps absent, null and value to the choice types`() {
+        val map = mapOf(1L to 30, 2L to null)
+        assertThat(map.reminderOverrideFor(1L)).isEqualTo(ReminderOverride.Minutes(30))
+        assertThat(map.reminderOverrideFor(2L)).isEqualTo(ReminderOverride.None)
+        assertThat(map.reminderOverrideFor(3L)).isEqualTo(ReminderOverride.Inherit)
+    }
+
+    @Test
+    fun `applyReminderOverride writes, clears and removes entries`() {
+        val map = mutableMapOf<Long, Int?>()
+        map.applyReminderOverride(1L, ReminderOverride.Minutes(45))
+        assertThat(map).containsExactly(1L, 45)
+
+        map.applyReminderOverride(1L, ReminderOverride.None)
+        assertThat(map[1L]).isNull()
+        assertThat(map).containsKey(1L)
+
+        map.applyReminderOverride(1L, ReminderOverride.Inherit)
+        assertThat(map).doesNotContainKey(1L)
+    }
+}

core-reminders/src/test/kotlin/de/jeanlucmakiola/floret/reminders/ReminderOverrideCodecTest.kt

@@ -0,0 +1,52 @@
+package de.jeanlucmakiola.floret.reminders
+
+import com.google.common.truth.Truth.assertThat
+import org.junit.jupiter.api.Test
+
+class ReminderOverrideCodecTest {
+
+    private val codec = ReminderOverrideCodec.DEFAULT
+
+    @Test
+    fun `round-trips ids, minutes and explicit none`() {
+        val map = mapOf(12L to 30, 7L to null, 3L to 0)
+        assertThat(codec.parse(codec.serialize(map))).isEqualTo(map)
+    }
+
+    @Test
+    fun `null or blank parses to empty`() {
+        assertThat(codec.parse(null)).isEmpty()
+        assertThat(codec.parse("")).isEmpty()
+        assertThat(codec.parse("   ")).isEmpty()
+    }
+
+    @Test
+    fun `empty map serializes to empty string`() {
+        assertThat(codec.serialize(emptyMap())).isEmpty()
+    }
+
+    @Test
+    fun `none token decodes to a null value`() {
+        assertThat(codec.parse("7:none")).isEqualTo(mapOf(7L to null))
+    }
+
+    @Test
+    fun `garbage entries are dropped, valid ones kept`() {
+        assertThat(codec.parse("12:30;garbage;x:5;9:notnum;4:10"))
+            .isEqualTo(mapOf(12L to 30, 4L to 10))
+    }
+
+    @Test
+    fun `a custom dialect keeps a separate on-disk format`() {
+        // Calendula's dialect: id=minutes entries.
+        val calendula = ReminderOverrideCodec(entrySep = ";", keyValueSep = "=", noneToken = "none")
+        val map = mapOf(12L to 30, 7L to null)
+        val stored = calendula.serialize(map)
+
+        assertThat(stored).contains("12=30")
+        assertThat(stored).contains("7=none")
+        assertThat(calendula.parse(stored)).isEqualTo(map)
+        // The Agendula dialect cannot read Calendula's bytes — the formats are distinct.
+        assertThat(codec.parse(stored)).isEmpty()
+    }
+}

docs/ARCHITECTURE.md

@@ -0,0 +1,147 @@
+# floret-kit — architecture
+
+How the kit is structured, built, and consumed **as it stands today**. For what
+is and isn't extracted, see [`ROADMAP.md`](ROADMAP.md); for the practical how of
+adding a module, see [`../CONTRIBUTING.md`](../CONTRIBUTING.md).
+
+---
+
+## 1. The thesis in one sentence
+
+floret-kit is a Gradle build of small, focused modules — plumbing and a Material
+3 Expressive design layer — that the family's apps draw from instead of
+re-deriving the same code. The whole design hangs off one rule:
+
+> Share the **mechanics**, keep the **look** per-app.
+
+Theme machinery, content-provider plumbing, and component primitives are shared;
+seed colours, palettes, identity chips, domain types, and app-specific wording
+stay in each app. The kit never knows about a specific app's domain.
+
+---
+
+## 2. How an app consumes the kit
+
+Each app embeds this repo as a **git submodule** and wires it in as a Gradle
+**composite build**. The kit is therefore always built **from source** — there
+are no published binaries — which keeps every consuming app reproducible (a
+requirement for official F-Droid).
+
+```kotlin
+// <app>/settings.gradle.kts
+includeBuild("floret-kit")
+```
+```kotlin
+// <app>/app/build.gradle.kts
+implementation("de.jeanlucmakiola.floret:core-time")
+implementation("de.jeanlucmakiola.floret:components")
+```
+
+Every module sets `group = "de.jeanlucmakiola.floret"` (via the root build's
+`subprojects {}`), so Gradle's dependency substitution maps
+`de.jeanlucmakiola.floret:<module>` to the local `project(":<module>")` of the
+included build. Editing the kit is picked up by the app's next build with no
+publish step.
+
+Each app **pins a specific kit commit** through its submodule gitlink. So a
+breaking change in the kit can't reach an app until that app deliberately
+re-pins — apps stay on independent cadences (important while Calendula ships and
+Agendula moves fast).
+
+### SDK location for the included build
+
+An included Android build needs to locate the Android SDK independently of the
+host app. Provide it via:
+
+- **CI:** an `ANDROID_HOME` env var (the apps set it at the job level), or
+- **locally:** a gitignored `<app>/floret-kit/local.properties` with `sdk.dir`.
+
+Pure-JVM modules (`core-time`) need neither.
+
+### Submodules in CI / F-Droid
+
+Consuming apps must check out submodules (`submodules: recursive` in the
+checkout step) so `floret-kit/` isn't empty. For an app published via **official
+F-Droid reproducible builds** (Calendula), the fdroiddata recipe additionally
+needs `submodules: true` on the build entry, and the app's reproducibility guard
+should scan the submodule's Gradle scripts (see §5).
+
+---
+
+## 3. Module layering
+
+| Layer | Modules | Notes |
+|---|---|---|
+| Plumbing | `core-time` (JVM) | Pure logic; no Android, no deps. |
+| Plumbing | `core-crash` (Android) | Self-contained subsystem; parameterized per app. |
+| Design — identity | `identity` (Android) | Theme factory + motion. App supplies seed/palette. |
+| Design — components | `components` (Android) | Shared Compose primitives. App composes screens. |
+
+Dependencies between modules are kept minimal: `core-time` depends on nothing in
+the kit; `identity` and `components` depend only on Compose + (for components)
+`material-icons-core`. There is no app-level or cross-domain coupling.
+
+Each module's package is `de.jeanlucmakiola.floret.<area>` (e.g.
+`de.jeanlucmakiola.floret.components`).
+
+---
+
+## 4. Module types & the build
+
+Two kinds of module:
+
+- **JVM library** (`core-time`) — `org.jetbrains.kotlin.jvm`, `jvmTarget = 17`,
+  JUnit 5 + Truth tests. The right home for pure logic; cheapest to build and
+  test.
+- **Android library** (`core-crash`, `identity`, `components`) —
+  `com.android.library` + the Compose plugin, `compileSdk 37` / `minSdk 29`.
+
+> **AGP 9.x provides built-in Kotlin compilation.** Android modules therefore
+> apply only `com.android.library` and `org.jetbrains.kotlin.plugin.compose` —
+> **not** a separate `org.jetbrains.kotlin.android` plugin (applying it errors).
+> They set `jvmTarget` directly in a `kotlin { compilerOptions { … } }` block.
+
+Versions live in [`gradle/libs.versions.toml`](../gradle/libs.versions.toml),
+kept in lockstep with the apps' catalogs.
+
+---
+
+## 5. Reproducibility rules
+
+Because consuming apps build the kit from source — and at least one publishes via
+official F-Droid reproducible builds — the kit follows the same invariants:
+
+1. **No `foojay` toolchain resolver**, anywhere (not even as a token in a
+   comment). It can fetch a JDK over the network at build time, which the offline
+   F-Droid source scanner rejects. Modules set `jvmTarget` directly instead of
+   using a Java toolchain block that would need a resolver.
+2. **No published artifacts.** Built from source, pinned by commit.
+3. Android library modules emit no APK-level metadata of their own (no
+   `buildConfig`); the consuming app controls APK-level reproducibility
+   (`vcsInfo`/`dependenciesInfo`).
+
+A consuming app's reproducibility guard should scan the submodule's `*.gradle.kts`
+for the resolver too, since the included build is part of the from-source graph.
+
+---
+
+## 6. The design-divergence contract
+
+The design modules (`identity`, `components`) carry the family's look, so they
+extract **mechanics** and leave **identity** to the app:
+
+- `identity` exposes a theme **factory**; each app passes its own seed-derived
+  `lightScheme`/`darkScheme` and typography. Seed colours and hand-tuned
+  fallbacks are never shared constants.
+- `components` are app-agnostic primitives. Where two apps differ, the
+  difference is an explicit **parameter** (e.g. `InlineTextField`'s
+  `capitalization`) or a **callback**, never a silently-picked winner. Apps keep
+  their own identity chips/icons and compose their own screens.
+- **String resources** in the kit are English **fallbacks**; an app overrides
+  them (with its localized values) via resource merge. App-specific wording
+  stays in the app.
+
+When a primitive is shared by adopting one app's version as canonical (e.g.
+`components`' `GroupedSurface` follows Agendula's cleaner abstraction), that is a
+deliberate, signed-off convergence — the other app's surfaces change when it
+re-pins, reviewable at that point.

docs/README.md

@@ -0,0 +1,26 @@
+# floret-kit — documentation
+
+floret-kit is the shared **Material 3 Expressive design system + plumbing** for
+the Floret family of Android apps
+([Calendula](https://gitea.jeanlucmakiola.de/makiolaj/calendula),
+[Agendula](https://gitea.jeanlucmakiola.de/makiolaj/agendula), and future
+siblings). It is consumed from source as a git submodule + Gradle composite
+build. See the top-level [`../README.md`](../README.md) for the pitch.
+
+## Index
+
+| Doc | What it covers |
+|---|---|
+| [`ARCHITECTURE.md`](ARCHITECTURE.md) | How the kit is built and **consumed** — the module layering, JVM vs Android-library modules, the submodule + composite-build model, and the reproducibility rules. Start here. |
+| [`ROADMAP.md`](ROADMAP.md) | **What's extracted, what's deferred, and what's deliberately not shared** — the module status and the divergence decisions from the cross-app survey. |
+| [`../CONTRIBUTING.md`](../CONTRIBUTING.md) | The practical how — adding a module, the no-app-coupling rules, build/test, and how an app adopts the kit. |
+| [`../CHANGELOG.md`](../CHANGELOG.md) | Keep a Changelog; what each module added. |
+
+## The one principle
+
+> Share the **mechanics**, keep the **look** per-app.
+
+Theme machinery, plumbing, and component primitives are shared; seed colours,
+palettes, identity chips, and app-specific wording stay in each app. This is what
+lets the family read as one design language without homogenising apps that are
+meant to have distinct personalities.

docs/ROADMAP.md

@@ -0,0 +1,68 @@
+# floret-kit — roadmap
+
+What's extracted, what's deferred, and what's deliberately **not** shared. The
+defer/skip calls come from a cross-app survey of both Calendula and Agendula —
+the guiding rule is to share only what is genuinely common, and to keep
+divergent or app-specific code where it lives.
+
+---
+
+## Extracted (done)
+
+| Module | Type | Consumers |
+|---|---|---|
+| `core-time` | JVM | Agendula (and Calendula's pending branch) |
+| `core-crash` | Android | Agendula |
+| `identity` | Android | Agendula |
+| `components` | Android | Agendula |
+
+See [`../CHANGELOG.md`](../CHANGELOG.md) for the contents of each.
+
+---
+
+## Deferred / not yet worth it
+
+- **`core-prefs`** (DataStore base: `ThemeMode`, `dynamicColor`, the typed
+  wrapper, `toEnum()`) and **`core-di`** (`@IoDispatcher` + provider) — genuinely
+  shared but **low value**: pure relocation, no new capability, the shared
+  surface is tiny once the store name and bindings stay app-local. Sensible to
+  defer until a third app makes the duplication hurt.
+- **`ReminderFormatting`** (`ReminderUnit` + `reminderLeadTimeLabel` +
+  `decomposeReminder`) — the labels are `@Composable` over app-specific
+  `R.plurals`, and the presets differ per app. Extract later behind a
+  **label/preset callback API**, not before.
+
+## Deferred — needs migration first
+
+- **`core-provider`** (the ContentProvider seam: `ColumnReader`, failures,
+  observer→Flow) — the two apps' `ColumnReader`s diverged (Calendula index-based,
+  Agendula name-based + null-safe). True sharing means migrating Calendula to the
+  better name-based design first (~a few hundred LOC), so it waits until Calendula
+  is actively on the kit.
+
+## Not shared (by design)
+
+- **A generic Settings scaffold** — the two apps' settings *domains* are too
+  divergent for a config-driven `SettingsScaffold` to stay readable. The win is
+  captured instead at the **component** level (shared `GroupedRow`/section
+  primitives + `CollapsingScaffold` + `OptionPicker`); each app composes its own
+  settings from those.
+- **`core-reminders`** (unified) — Agendula self-schedules alarms (pull),
+  Calendula is provider-event-driven (push). Opposite architectures over
+  incompatible data models; forcing a shared abstraction would be leaky. A tiny
+  `core-notification` (idempotent channel setup, `POST_NOTIFICATIONS` checks)
+  *might* land later; schedulers stay app-local.
+- Domain-specific UI (date/time fields tied to a domain, calendar/timeline
+  widgets, recurrence text, domain pickers) and all string wording — these encode
+  each app's model and resist parameterization.
+
+---
+
+## Consumers & cadence
+
+- **Agendula** consumes the kit on `main` (active development).
+- **Calendula** (ships via official F-Droid reproducible builds) has a pending
+  adoption branch. Bringing it onto the kit is where the canonical-`GroupedSurface`
+  convergence becomes visible, and where the F-Droid reproducibility checklist
+  (`submodules: true` in the recipe; the repro guard scanning the submodule)
+  applies — see [`ARCHITECTURE.md`](ARCHITECTURE.md) §2 and §5.

gradle/libs.versions.toml

@@ -4,6 +4,8 @@
 agp = "9.2.1"
 kotlin = "2.3.21"
 coreKtx = "1.19.0"
+appcompat = "1.7.1"
+activityCompose = "1.13.0"
 composeBom = "2026.05.01"
 # Material 3 Expressive APIs live in the 1.5 alpha line; pinned to override the BOM.
 material3 = "1.5.0-alpha21"
@@ -13,10 +15,13 @@ truth = "1.4.5"
 
 [libraries]
 androidx-core-ktx = { group = "androidx.core", name = "core-ktx", version.ref = "coreKtx" }
+androidx-appcompat = { group = "androidx.appcompat", name = "appcompat", version.ref = "appcompat" }
+androidx-activity-compose = { group = "androidx.activity", name = "activity-compose", version.ref = "activityCompose" }
 androidx-compose-bom = { group = "androidx.compose", name = "compose-bom", version.ref = "composeBom" }
 androidx-ui = { group = "androidx.compose.ui", name = "ui" }
 androidx-foundation = { group = "androidx.compose.foundation", name = "foundation" }
 androidx-material3 = { group = "androidx.compose.material3", name = "material3", version.ref = "material3" }
+androidx-animation = { group = "androidx.compose.animation", name = "animation" }
 androidx-material-icons-core = { group = "androidx.compose.material", name = "material-icons-core" }
 
 junit-jupiter-api = { group = "org.junit.jupiter", name = "junit-jupiter-api", version.ref = "junit" }

identity/build.gradle.kts

@@ -36,4 +36,7 @@ dependencies {
     implementation(libs.androidx.ui)
     implementation(libs.androidx.foundation)
     implementation(libs.androidx.material3)
+    implementation(libs.androidx.animation)
+    // activity-compose for PredictiveBackHandler + BackEventCompat (the back-gesture peek).
+    implementation(libs.androidx.activity.compose)
 }

identity/src/main/kotlin/de/jeanlucmakiola/floret/identity/Motion.kt

@@ -0,0 +1,87 @@
+package de.jeanlucmakiola.floret.identity
+
+import android.provider.Settings
+import androidx.activity.BackEventCompat
+import androidx.activity.compose.PredictiveBackHandler
+import androidx.compose.animation.core.Animatable
+import androidx.compose.animation.core.FastOutSlowInEasing
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.graphicsLayer
+import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.unit.dp
+import kotlin.coroutines.cancellation.CancellationException
+
+/**
+ * Whether the user has asked the system to remove animations (Settings →
+ * Accessibility → "Remove animations", which sets the global animator duration
+ * scale to 0). Compose animations do *not* honour this platform flag on their
+ * own, so the shared motion helpers check it and fall back to no spatial
+ * movement — respecting the vestibular intent of the setting while keeping state
+ * changes legible.
+ *
+ * Read once at composition; the scale changes rarely and only takes full effect
+ * after a process restart anyway.
+ */
+@Composable
+fun rememberReduceMotion(): Boolean {
+    val resolver = LocalContext.current.contentResolver
+    return remember(resolver) {
+        Settings.Global.getFloat(resolver, Settings.Global.ANIMATOR_DURATION_SCALE, 1f) == 0f
+    }
+}
+
+/**
+ * The standard Android predictive-back transform for a full-screen surface: as
+ * the back gesture is dragged, the surface scales toward ~90%, shifts toward the
+ * swiped edge and rounds its corners, previewing what's behind. Completing the
+ * gesture invokes [onBack]; cancelling springs it back.
+ *
+ * A drop-in replacement for a screen's own `BackHandler(onBack)` — register it
+ * once and apply the returned [Modifier] to that screen's root so the preview
+ * respects the same back semantics. Under reduced motion the visual preview is
+ * skipped (the back still works); on API < 34 the system delivers no progress,
+ * so it degrades to a plain back. Shared so the family's apps preview the same
+ * way.
+ *
+ * @param enabled gate the handler — e.g. set false while a screen's own inner
+ *   back (a sub-section) should take the gesture instead.
+ */
+@Composable
+fun Modifier.predictiveBack(
+    onBack: () -> Unit,
+    enabled: Boolean = true,
+    reduceMotion: Boolean = rememberReduceMotion(),
+): Modifier {
+    val progress = remember { Animatable(0f) }
+    var fromLeftEdge by remember { mutableStateOf(true) }
+
+    PredictiveBackHandler(enabled = enabled) { events ->
+        try {
+            events.collect { event ->
+                fromLeftEdge = event.swipeEdge == BackEventCompat.EDGE_LEFT
+                progress.snapTo(FastOutSlowInEasing.transform(event.progress))
+            }
+            onBack()
+            progress.snapTo(0f)
+        } catch (_: CancellationException) {
+            progress.animateTo(0f)
+        }
+    }
+
+    if (reduceMotion) return this
+    return this.graphicsLayer {
+        val p = progress.value
+        val scale = 1f - 0.1f * p
+        scaleX = scale
+        scaleY = scale
+        translationX = (if (fromLeftEdge) 1f else -1f) * 24.dp.toPx() * p
+        shape = RoundedCornerShape(32.dp.toPx() * p)
+        clip = p > 0f
+    }
+}

identity/src/main/kotlin/de/jeanlucmakiola/floret/identity/Transitions.kt

@@ -0,0 +1,91 @@
+package de.jeanlucmakiola.floret.identity
+
+import androidx.compose.animation.ContentTransform
+import androidx.compose.animation.EnterTransition
+import androidx.compose.animation.ExitTransition
+import androidx.compose.animation.expandVertically
+import androidx.compose.animation.fadeIn
+import androidx.compose.animation.fadeOut
+import androidx.compose.animation.shrinkVertically
+import androidx.compose.animation.slideInVertically
+import androidx.compose.animation.togetherWith
+import androidx.compose.foundation.lazy.LazyItemScope
+import androidx.compose.material3.ExperimentalMaterial3ExpressiveApi
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+
+/**
+ * The family's content transitions, driven by the active M3 Expressive motion
+ * scheme so every app reveals, collapses and re-lays-out the same way. Each
+ * honours [rememberReduceMotion]: when the user has asked the system to remove
+ * animations, the spatial movement is dropped and only a quick fade remains.
+ *
+ * Drawn from Calendula's motion helpers; pair [expandEnter] with [collapseExit]
+ * on an `AnimatedVisibility`, use [itemEnter] for content revealed once it
+ * resolves, [animateItemMotion] for `LazyColumn`/`LazyRow` row relayout, and
+ * [fadeThrough] to swap whole blocks with no spatial direction.
+ */
+
+/**
+ * Enter for a vertically-revealed section (expandable rows, inline fields):
+ * height grows from the top while fading in; a quick fade only under reduced
+ * motion. Pair with [collapseExit].
+ */
+@OptIn(ExperimentalMaterial3ExpressiveApi::class)
+@Composable
+fun expandEnter(reduceMotion: Boolean = rememberReduceMotion()): EnterTransition {
+    val fade = fadeIn(MaterialTheme.motionScheme.fastEffectsSpec())
+    return if (reduceMotion) fade else expandVertically(MaterialTheme.motionScheme.fastSpatialSpec()) + fade
+}
+
+/** Exit counterpart to [expandEnter]: shrink + fade, or fade only under reduced motion. */
+@OptIn(ExperimentalMaterial3ExpressiveApi::class)
+@Composable
+fun collapseExit(reduceMotion: Boolean = rememberReduceMotion()): ExitTransition {
+    val fade = fadeOut(MaterialTheme.motionScheme.fastEffectsSpec())
+    return if (reduceMotion) fade else shrinkVertically(MaterialTheme.motionScheme.fastSpatialSpec()) + fade
+}
+
+/**
+ * Enter for content revealed by an `AnimatedContent`/`AnimatedVisibility` (e.g.
+ * results once a query resolves): a gentle rise + fade; fade only under reduced
+ * motion.
+ */
+@OptIn(ExperimentalMaterial3ExpressiveApi::class)
+@Composable
+fun itemEnter(reduceMotion: Boolean = rememberReduceMotion()): EnterTransition {
+    val fade = fadeIn(MaterialTheme.motionScheme.fastEffectsSpec())
+    return if (reduceMotion) fade else fade + slideInVertically(MaterialTheme.motionScheme.fastSpatialSpec()) { h -> h / 6 }
+}
+
+/**
+ * `LazyItemScope.animateItem` wired to the app's motion scheme instead of
+ * Compose's default spring, so list rows fade/relocate consistently. Returns a
+ * bare [Modifier] under reduced motion so rows snap into place. Requires stable
+ * item keys.
+ */
+@OptIn(ExperimentalMaterial3ExpressiveApi::class)
+@Composable
+fun LazyItemScope.animateItemMotion(reduceMotion: Boolean = rememberReduceMotion()): Modifier =
+    if (reduceMotion) {
+        Modifier
+    } else {
+        Modifier.animateItem(
+            fadeInSpec = MaterialTheme.motionScheme.fastEffectsSpec(),
+            placementSpec = MaterialTheme.motionScheme.fastSpatialSpec(),
+            fadeOutSpec = MaterialTheme.motionScheme.fastEffectsSpec(),
+        )
+    }
+
+/**
+ * Cross-fade [ContentTransform] for swapping whole screens or blocks with no
+ * meaningful spatial direction (e.g. onboarding gates). Pure opacity, so it
+ * doubles as its own reduced-motion form.
+ */
+@OptIn(ExperimentalMaterial3ExpressiveApi::class)
+@Composable
+fun fadeThrough(): ContentTransform {
+    val fade = MaterialTheme.motionScheme.fastEffectsSpec<Float>()
+    return fadeIn(fade).togetherWith(fadeOut(fade))
+}

settings.gradle.kts

@@ -32,6 +32,8 @@ dependencyResolutionManagement {
 rootProject.name = "floret-kit"
 
 include(":core-time")
+include(":core-reminders")
+include(":core-locale")
 include(":core-crash")
 include(":identity")
 include(":components")