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/androidMain/kotlin/com/example/casera/MainActivity.kt

@@ -35,6 +35,7 @@ import kotlinx.coroutines.launch
 
 class MainActivity : ComponentActivity(), SingletonImageLoader.Factory {
     private var deepLinkResetToken by mutableStateOf<String?>(null)
+    private var navigateToTaskId by mutableStateOf<Int?>(null)
     private lateinit var billingManager: BillingManager
 
     override fun onCreate(savedInstanceState: Bundle?) {
@@ -54,8 +55,9 @@ class MainActivity : ComponentActivity(), SingletonImageLoader.Factory {
         // Initialize BillingManager for subscription management
         billingManager = BillingManager.getInstance(applicationContext)
 
-        // Handle deep link from intent
+        // Handle deep link and notification navigation from intent
         handleDeepLink(intent)
+        handleNotificationNavigation(intent)
 
         // Request notification permission and setup FCM
         setupFCM()
@@ -68,6 +70,10 @@ class MainActivity : ComponentActivity(), SingletonImageLoader.Factory {
                 deepLinkResetToken = deepLinkResetToken,
                 onClearDeepLinkToken = {
                     deepLinkResetToken = null
+                },
+                navigateToTaskId = navigateToTaskId,
+                onClearNavigateToTask = {
+                    navigateToTaskId = null
                 }
             )
         }
@@ -180,6 +186,15 @@ class MainActivity : ComponentActivity(), SingletonImageLoader.Factory {
     override fun onNewIntent(intent: Intent) {
         super.onNewIntent(intent)
         handleDeepLink(intent)
+        handleNotificationNavigation(intent)
+    }
+
+    private fun handleNotificationNavigation(intent: Intent?) {
+        val taskId = intent?.getIntExtra(NotificationActionReceiver.EXTRA_NAVIGATE_TO_TASK, -1)
+        if (taskId != null && taskId != -1) {
+            Log.d("MainActivity", "Navigating to task from notification: $taskId")
+            navigateToTaskId = taskId
+        }
     }
 
     private fun handleDeepLink(intent: Intent?) {