Add actionable push notifications for iOS and Android

iOS:
- Add notification categories with action buttons (complete, view, cancel, etc.)
- Handle notification actions in AppDelegate with API calls
- Add navigation to specific task from notification tap
- Register UNNotificationCategory for each task state

Android:
- Add NotificationActionReceiver BroadcastReceiver for handling actions
- Update MyFirebaseMessagingService to show action buttons
- Add deep link handling in MainActivity for task navigation
- Register receiver in AndroidManifest.xml

Shared:
- Add navigateToTaskId parameter to App for cross-platform navigation
- Add notification observers in MainTabView/AllTasksView for refresh

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

composeApp/src/commonMain/kotlin/com/example/casera/App.kt

@@ -65,7 +65,9 @@ import casera.composeapp.generated.resources.compose_multiplatform
 @Preview
 fun App(
     deepLinkResetToken: String? = null,
-    onClearDeepLinkToken: () -> Unit = {}
+    onClearDeepLinkToken: () -> Unit = {},
+    navigateToTaskId: Int? = null,
+    onClearNavigateToTask: () -> Unit = {}
 ) {
     var isLoggedIn by remember { mutableStateOf(DataManager.authToken.value != null) }
     var isVerified by remember { mutableStateOf(false) }
@@ -73,6 +75,15 @@ fun App(
     var hasCompletedOnboarding by remember { mutableStateOf(DataManager.hasCompletedOnboarding.value) }
     val navController = rememberNavController()
 
+    // Handle navigation from notification tap
+    LaunchedEffect(navigateToTaskId) {
+        if (navigateToTaskId != null && isLoggedIn && isVerified) {
+            // Navigate to tasks screen (task detail view is handled within the screen)
+            navController.navigate(TasksRoute)
+            onClearNavigateToTask()
+        }
+    }
+
     // Check for stored token and verification status on app start
     LaunchedEffect(Unit) {
         val hasToken = DataManager.authToken.value != null