M5: push (FCM + ntfy) + offline catch-up + background notifications

Server (gateway-plugin):
- push.py: FCM (HTTP v1 service-account / legacy key) + ntfy backends; NtfyBackend.server_url for app discovery
- adapter.py: push on offline broadcast + high-priority push when live; fcm.register; server_caps.push_ntfy_server; outbox now ALWAYS appends so a reconnecting app catches up on live-delivered frames (fixes empty chat after notification tap / activity recreation)
- protocol.py / ws_server.py / outbox.py / plugin.yaml: M5 frames + env vars

App (Kotlin CMP):
- Protocol.kt: notification / fcm.register / sync frames + push caps
- GatewayClient.kt: hello carries push creds; auto-sync on reconnect
- IrisController.kt: banners, deep-link, notifyMessageIfBackgrounded (system notification on a regular reply when backgrounded)
- Android: PlatformPush, AppBridge, IrisNotifications, NtfyListenerService, IrisFirebaseMessagingService, AndroidPush, AndroidSecureStore
- Desktop: DesktopPush, DesktopSecureStore
- build files + manifest (permissions, services, deep-links)

Tests: 35-test tests/gateway/test_android.py suite passes (incl. new regression test_live_delivered_frame_still_parked_for_sync). E2E verified on device: push fire, reconnect sync, background notification, and message replay after ChatStore reset.

app/androidApp/src/main/AndroidManifest.xml

@@ -3,6 +3,11 @@
 
     <uses-permission android:name="android.permission.INTERNET" />
     <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
+    <!-- M5: post push notifications (runtime permission on API 33+). -->
+    <uses-permission android:name="android.permission.POST_NOTIFICATIONS" />
+    <!-- M5: ntfy listener foreground service (dataSync type on API 34). -->
+    <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
+    <uses-permission android:name="android.permission.FOREGROUND_SERVICE_DATA_SYNC" />
 
     <application
         android:label="Iris"
@@ -18,6 +23,19 @@
                 <action android:name="android.intent.action.MAIN" />
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
+            <!-- M5: deep link from a push notification tap (custom action,
+                 no compile-time dependency from the shared module). -->
+            <intent-filter>
+                <action android:name="dev.iris.app.OPEN_CHAT" />
+                <category android:name="android.intent.category.DEFAULT" />
+            </intent-filter>
+            <!-- M5: iris:// deep link (external links / share targets). -->
+            <intent-filter>
+                <action android:name="android.intent.action.VIEW" />
+                <category android:name="android.intent.category.DEFAULT" />
+                <category android:name="android.intent.category.BROWSABLE" />
+                <data android:scheme="iris" android:host="chat" />
+            </intent-filter>
         </activity>
 
         <!-- M4: serve cached media/documents to other apps (ACTION_VIEW). -->
@@ -30,6 +48,22 @@
                 android:name="android.support.FILE_PROVIDER_PATHS"
                 android:resource="@xml/iris_file_paths" />
         </provider>
+
+        <!-- M5: ntfy listener (foreground service; subscribes to the device
+             topic and posts push notifications). -->
+        <service
+            android:name="iris.platform.NtfyListenerService"
+            android:exported="false"
+            android:foregroundServiceType="dataSync" />
+
+        <!-- M5: FCM handler (inert without a Firebase project). -->
+        <service
+            android:name="iris.platform.IrisFirebaseMessagingService"
+            android:exported="false">
+            <intent-filter>
+                <action android:name="com.google.firebase.MESSAGING_EVENT" />
+            </intent-filter>
+        </service>
     </application>
 
 </manifest>