fix: reschedule when exact alarms are allowed again

Granting "Alarms & reminders" again left the next alarm on the inexact
fallback until something else re-registered it. The system's permission
broadcast now reschedules alarms and timers.

app/src/main/AndroidManifest.xml

@@ -269,6 +269,7 @@
                 <action android:name="android.intent.action.TIME_SET" />
                 <action android:name="android.intent.action.TIMEZONE_CHANGED" />
                 <action android:name="android.intent.action.MY_PACKAGE_REPLACED" />
+                <action android:name="android.app.action.SCHEDULE_EXACT_ALARM_PERMISSION_STATE_CHANGED" />
             </intent-filter>
         </receiver>
 

app/src/main/java/de/jeanlucmakiola/clockula/alarm/receiver/SystemEventReceiver.kt

@@ -17,7 +17,9 @@ import javax.inject.Inject
 /**
  * Everything that invalidates a registration: a reboot clears AlarmManager, an
  * app update clears it too, and a clock or zone change moves what "07:00" means.
- * All four are answered the same way — re-resolve from now.
+ * All four are answered the same way — re-resolve from now. So is the user
+ * granting "Alarms & reminders" again, which turns an inexact registration
+ * back into an exact one.
  *
  * Both engines are told, in that order. For the timers a clock change
  * reschedules nothing (their slot is elapsed-realtime anchored); it re-anchors
@@ -65,6 +67,11 @@ class SystemEventReceiver : HiltBroadcastReceiver() {
                         stopwatchEngine.resync()
                     }
 
+                    ACTION_EXACT_ALARM_PERMISSION_CHANGED -> {
+                        engine.reschedule()
+                        timerEngine.resync()
+                    }
+
                     Intent.ACTION_TIME_CHANGED,
                     Intent.ACTION_TIMEZONE_CHANGED,
                     -> {
@@ -93,4 +100,10 @@ class SystemEventReceiver : HiltBroadcastReceiver() {
             }
         }
     }
+
+    private companion object {
+        /** `AlarmManager.ACTION_SCHEDULE_EXACT_ALARM_PERMISSION_STATE_CHANGED`, API 31+. */
+        const val ACTION_EXACT_ALARM_PERMISSION_CHANGED =
+            "android.app.action.SCHEDULE_EXACT_ALARM_PERMISSION_STATE_CHANGED"
+    }
 }