feat(reminders): snooze + dismiss notification actions

Add "Snooze" and "Dismiss" action buttons to reminder notifications.

The app is otherwise pure provider-broadcast (the Etar model): the calendar
provider fires EVENT_REMINDER and we post the notification, then mark the
CalendarAlerts row fired. A snoozed reminder has no provider backing — its
row is already fired — so snooze self-schedules an exact alarm to re-show
the same notification, while primary delivery is left unchanged.

- ReminderActionReceiver (not exported): SNOOZE cancels + schedules a
  re-show, DISMISS cancels, SHOW (the alarm) re-posts so it can be snoozed
  or dismissed again.
- ReminderSnoozeScheduler: setExactAndAllowWhileIdle, with an inexact
  allow-while-idle fallback if exact alarms are revoked (API 31-32).
- ReminderNotifier: two actions + cancel().
- snoozeMinutes pref (default 10) in Settings -> Notifications, OptionPicker
  presets 5/10/15/30/60.
- Manifest: USE_EXACT_ALARM + SCHEDULE_EXACT_ALARM (maxSdk 32) + receiver.
- New ic_notification_snooze/_dismiss drawables, duration plurals, en+de
  strings, snooze-pref tests.

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

app/src/test/java/de/jeanlucmakiola/calendula/data/prefs/SettingsPrefsTest.kt

@@ -233,6 +233,23 @@ class SettingsPrefsTest {
         assertThat(prefs.allDayReminderTimeMinutes.first()).isEqualTo(0)
     }
 
+    @Test
+    fun `snooze duration defaults to 10 minutes`(@TempDir tempDir: Path) = runTest {
+        val prefs = SettingsPrefs(newDataStore(tempDir))
+        assertThat(prefs.snoozeMinutes.first()).isEqualTo(10)
+    }
+
+    @Test
+    fun `snooze duration round-trips and clamps to at least one minute`(
+        @TempDir tempDir: Path,
+    ) = runTest {
+        val prefs = SettingsPrefs(newDataStore(tempDir))
+        prefs.setSnoozeMinutes(30)
+        assertThat(prefs.snoozeMinutes.first()).isEqualTo(30)
+        prefs.setSnoozeMinutes(0)
+        assertThat(prefs.snoozeMinutes.first()).isEqualTo(1)
+    }
+
     @Test
     fun `explicit week-start prefs resolve regardless of locale`() {
         assertThat(WeekStartPref.MONDAY.resolveFirstDay(Locale.US)).isEqualTo(DayOfWeek.MONDAY)