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/AndroidManifest.xml

@@ -65,6 +65,19 @@
         <meta-data
             android:name="com.google.firebase.messaging.default_notification_channel_id"
             android:value="@string/default_notification_channel_id" />
+
+        <!-- Notification Action Receiver -->
+        <receiver
+            android:name=".NotificationActionReceiver"
+            android:exported="false">
+            <intent-filter>
+                <action android:name="com.example.casera.ACTION_VIEW_TASK" />
+                <action android:name="com.example.casera.ACTION_COMPLETE_TASK" />
+                <action android:name="com.example.casera.ACTION_MARK_IN_PROGRESS" />
+                <action android:name="com.example.casera.ACTION_CANCEL_TASK" />
+                <action android:name="com.example.casera.ACTION_UNCANCEL_TASK" />
+            </intent-filter>
+        </receiver>
     </application>
 
 </manifest>