M8: app integration — navigation, :data bindings in both variants, FCM adapter, push notifications, hardening

:app binds every :core:model interface to :data in debug and release (AppDataModule, D-085); the
debug fakes module is gone. NavHost over all feature screens with the session gate (S-1, S-2, S-18),
bottom destinations from each screen's own bar, result snackbars, deep links (kvitt://invite and the
/i/<CODE> landing link) and notification taps. :adapter:fcm maps payload v1 to PushEvent and registers
by Firebase Installation ID (firebase-messaging 26, D-087). Push work runs in WorkManager: expedited
sync waited up to 20 s, then the notification from local data or the generic text. WorkManager uses
KvittWorkerFactory, Coil uses :data's ImageLoader, SyncTriggers on start and foreground, update check
in release only. Network security configs (debug cleartext, D-086; pinned-root variant), release
signing from local.properties, notification permission after the first sync.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TQd3pEP9UeN2uifbHknQ7B

android/adapter/fcm/build.gradle.kts

@@ -1,8 +1,13 @@
-// :adapter:fcm — Firebase Cloud Messaging, the only module that names the vendor (owned by M8). M2b ships the shell.
+// :adapter:fcm — Firebase Cloud Messaging, the only module that names the vendor (SPEC §6.2, owned by M8): the
+// FirebaseMessagingService, the FCM token calls, and the mapping of data messages to the project's own PushEvent.
 plugins {
     id("kvitt.android.library")
+    id("kvitt.android.hilt")
 }
 
 dependencies {
     implementation(project(":core:model"))
+    implementation(platform(libs.firebase.bom))
+    implementation(libs.firebase.messaging)
+    implementation(libs.kotlinx.coroutines.core)
 }