refactor(locale): draw per-app language from floret-kit core-locale

Replace the app-local AppLanguage with the shared
de.jeanlucmakiola.floret.locale.AppLanguage. The kit version is identical
except supportedTags() takes the locales_config XML res id as a parameter
(the kit can't reference the app's R), so the call site now passes
R.xml.locales_config. Wire the core-locale module into the app.

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

app/build.gradle.kts

@@ -160,6 +160,7 @@ dependencies {
 
     implementation(libs.kotlinx.datetime)
     implementation("de.jeanlucmakiola.floret:core-time")
+    implementation("de.jeanlucmakiola.floret:core-locale")
     implementation(libs.kotlinx.coroutines.core)
 
     debugImplementation(libs.androidx.ui.tooling)

app/src/main/java/de/jeanlucmakiola/calendula/ui/settings/AppLanguage.kt

@@ -1,78 +0,0 @@
-package de.jeanlucmakiola.calendula.ui.settings
-
-import android.content.Context
-import androidx.appcompat.app.AppCompatDelegate
-import androidx.core.os.LocaleListCompat
-import de.jeanlucmakiola.calendula.R
-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 res/xml/locales_config.xml.
- *
- * That file is the single source of truth for which languages we ship: 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 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): List<String> {
-        val tags = mutableListOf<String>()
-        val parser = context.resources.getXml(R.xml.locales_config)
-        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() }
-    }
-}

app/src/main/java/de/jeanlucmakiola/calendula/ui/settings/SettingsScreen.kt

@@ -50,6 +50,7 @@ import androidx.compose.material.icons.filled.Notifications
 import androidx.compose.material.icons.filled.Palette
 import androidx.compose.material.icons.filled.Translate
 import androidx.compose.material.icons.filled.Tune
+import de.jeanlucmakiola.floret.locale.AppLanguage
 import androidx.compose.material3.FilledTonalButton
 import androidx.compose.material3.Icon
 import androidx.compose.material3.MaterialTheme
@@ -298,7 +299,7 @@ private fun LanguageRow(position: Position) {
     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) }
+    val options = remember { listOf<String?>(null) + AppLanguage.supportedTags(context, R.xml.locales_config) }
 
     GroupedRow(
         title = stringResource(R.string.settings_language),