feat(mobile): replace Sentry with Firebase Crashlytics

Migrate error tracking from Sentry to Firebase Crashlytics.
Bump version to 1.0.4, add Discord notification triggers.

apps/mobile/firebase.json

@@ -1,6 +1,9 @@
 {
   "react-native": {
     "analytics_auto_collection_enabled": true,
-    "google_analytics_adid_collection_enabled": false
+    "google_analytics_adid_collection_enabled": false,
+    "crashlytics_auto_collection_enabled": true,
+    "crashlytics_debug_enabled": false,
+    "crashlytics_ndk_enabled": true
   }
 }