fix(edit): time picker dial honours the app 24h/12h setting (#27)

The event-form (and Settings) time picker seeded is24Hour from the
system TIME_12_24 override / device locale, ignoring the app's own
TimeFormatPref. So with the app set to 24h under an English locale the
dial still showed AM/PM, while every time label (which reads
LocalUse24HourFormat) showed 24h.

Seed the picker from LocalUse24HourFormat — the app-wide clock
convention already resolved once at the root from TimeFormatPref — so the
dial matches the labels. Drops the now-unused deviceUses24HourClock
helper.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/TimePickerAlert.kt

@@ -4,14 +4,9 @@ import androidx.compose.material3.AlertDialog
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.Text
 import androidx.compose.material3.TextButton
-import android.content.Context
-import android.content.res.Resources
-import android.provider.Settings
-import android.text.format.DateFormat
 import androidx.compose.material3.TimePicker
 import androidx.compose.material3.rememberTimePickerState
 import androidx.compose.runtime.Composable
-import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.res.stringResource
 import de.jeanlucmakiola.calendula.R
 import kotlinx.datetime.LocalTime
@@ -27,10 +22,13 @@ fun TimePickerAlert(
     onConfirm: (LocalTime) -> Unit,
     onDismiss: () -> Unit,
 ) {
+    // Honour the app's own time-format preference (the value every time label
+    // reads), not the system/locale clock — otherwise an explicit 24h setting
+    // still showed an AM/PM dial (issue #27).
     val state = rememberTimePickerState(
         initialHour = initial.hour,
         initialMinute = initial.minute,
-        is24Hour = deviceUses24HourClock(LocalContext.current),
+        is24Hour = LocalUse24HourFormat.current,
     )
     AlertDialog(
         onDismissRequest = onDismiss,
@@ -45,24 +43,3 @@ fun TimePickerAlert(
         text = { TimePicker(state = state) },
     )
 }
-
-/**
- * Whether the clock should read 24-hour, matching the rest of the device.
- *
- * [DateFormat.is24HourFormat] resolves a "locale default" system setting against
- * the *app's* context locale — and this app applies a per-app language
- * (AppCompatDelegate), so an English UI on a German-region phone would wrongly
- * read 12-hour while the system clock shows 24-hour. So we honour an explicit
- * system 12/24 override, and otherwise fall back to the **device** locale
- * (Resources.getSystem), not the app's.
- */
-private fun deviceUses24HourClock(context: Context): Boolean =
-    when (Settings.System.getString(context.contentResolver, Settings.System.TIME_12_24)) {
-        "24" -> true
-        "12" -> false
-        // 'a' is the AM/PM marker; a best-fit pattern without it is 24-hour.
-        else -> {
-            val deviceLocale = Resources.getSystem().configuration.locales[0]
-            !DateFormat.getBestDateTimePattern(deviceLocale, "jm").contains('a')
-        }
-    }