Draw core-time from floret-kit (TimeBridge) via submodule + composite build

Phase 1 of the shared-kit plan: Calendula becomes the second core-time consumer.
floret-kit is embedded as a git submodule and wired with includeBuild, so the
app depends on de.jeanlucmakiola.floret:core-time and Gradle substitutes the
local source module (built from source).

- Remove the app's TimeBridge (Instant <-> epoch millis) + its test; the helpers
  now live in core-time. Repoint the 7 call sites to de.jeanlucmakiola.floret.time.
- Calendula's richer time formatting (TimeFormat, 24h CompositionLocal) stays
  app-local by design.

Reproducible-build handling (Calendula publishes via official F-Droid repro):
- Pin the submodule to a foojay-free kit commit (the resolver would let a build
  fetch a JDK -> non-reproducible; the kit never used a toolchain block).
- Harden scripts/check_reproducible_release.sh to scan the included build's
  Gradle scripts for the toolchain-resolver invariant.
- Draft fdroiddata recipe: submodules: true (else F-Droid checks out an empty
  floret-kit/ and the from-source build fails).
- CI build checkouts fetch submodules recursively.

Clean composite build + unit tests + lintDebug + repro guard all green.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

app/build.gradle.kts

@@ -159,6 +159,7 @@ dependencies {
     implementation(libs.androidx.glance.material3)
 
     implementation(libs.kotlinx.datetime)
+    implementation("de.jeanlucmakiola.floret:core-time")
     implementation(libs.kotlinx.coroutines.core)
 
     debugImplementation(libs.androidx.ui.tooling)

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/CalendarDataSource.kt

@@ -1,5 +1,7 @@
 package de.jeanlucmakiola.calendula.data.calendar
 
+import de.jeanlucmakiola.floret.time.toEpochMillis
+import de.jeanlucmakiola.floret.time.toKotlinInstantFromEpochMillis
 import android.Manifest
 import android.content.ContentResolver
 import android.content.ContentUris

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/CalendarRepositoryImpl.kt

@@ -1,5 +1,6 @@
 package de.jeanlucmakiola.calendula.data.calendar
 
+import de.jeanlucmakiola.floret.time.toEpochMillis
 import de.jeanlucmakiola.calendula.data.di.IoDispatcher
 import de.jeanlucmakiola.calendula.data.prefs.CalendarPrefs
 import de.jeanlucmakiola.calendula.data.prefs.SettingsPrefs

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/EventDetailMapper.kt

@@ -1,5 +1,6 @@
 package de.jeanlucmakiola.calendula.data.calendar
 
+import de.jeanlucmakiola.floret.time.toKotlinInstantFromEpochMillis
 import android.provider.CalendarContract
 import android.util.Log
 import de.jeanlucmakiola.calendula.domain.AccessLevel

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/IcsExportMapper.kt

@@ -1,5 +1,6 @@
 package de.jeanlucmakiola.calendula.data.calendar
 
+import de.jeanlucmakiola.floret.time.toKotlinInstantFromEpochMillis
 import de.jeanlucmakiola.calendula.domain.EventStatus
 import de.jeanlucmakiola.calendula.domain.ics.IcsEvent
 import de.jeanlucmakiola.calendula.domain.ics.deriveIcsUid

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/InstanceMapper.kt

@@ -1,5 +1,6 @@
 package de.jeanlucmakiola.calendula.data.calendar
 
+import de.jeanlucmakiola.floret.time.toKotlinInstantFromEpochMillis
 import android.util.Log
 import de.jeanlucmakiola.calendula.domain.EventInstance
 

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/SearchMapper.kt

@@ -1,5 +1,6 @@
 package de.jeanlucmakiola.calendula.data.calendar
 
+import de.jeanlucmakiola.floret.time.toKotlinInstantFromEpochMillis
 import de.jeanlucmakiola.calendula.domain.EventInstance
 import de.jeanlucmakiola.calendula.domain.ics.parseRfc2445DurationMillis
 

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/TimeBridge.kt

@@ -1,7 +0,0 @@
-package de.jeanlucmakiola.calendula.data.calendar
-
-import kotlin.time.Instant
-
-fun Long.toKotlinInstantFromEpochMillis(): Instant = Instant.fromEpochMilliseconds(this)
-
-fun Instant.toEpochMillis(): Long = toEpochMilliseconds()

app/src/test/java/de/jeanlucmakiola/calendula/data/calendar/TimeBridgeTest.kt

@@ -1,26 +0,0 @@
-package de.jeanlucmakiola.calendula.data.calendar
-
-import com.google.common.truth.Truth.assertThat
-import kotlin.time.Instant
-import org.junit.jupiter.api.Test
-
-class TimeBridgeTest {
-
-    @Test
-    fun `epoch millis round-trips through Instant`() {
-        val original = 1_717_840_800_000L // 2024-06-08T10:00:00Z
-        val instant = original.toKotlinInstantFromEpochMillis()
-        assertThat(instant.toEpochMillis()).isEqualTo(original)
-    }
-
-    @Test
-    fun `zero millis maps to Instant epoch`() {
-        assertThat(0L.toKotlinInstantFromEpochMillis()).isEqualTo(Instant.fromEpochMilliseconds(0L))
-    }
-
-    @Test
-    fun `negative epoch millis is supported`() {
-        val original = -1_000_000L
-        assertThat(original.toKotlinInstantFromEpochMillis().toEpochMillis()).isEqualTo(original)
-    }
-}