feat(chat): message persistence + background notifications (#2)

* feat(chat): message persistence + background notifications

Two critical gaps for daily-driver use:

1. Message persistence (Room database):
   - New ChatMessageEntity / ChatMessageDao / HermesDatabase layer
   - Every user message, streaming token, tool result, and assistant
     reply is written to a local Room DB as it arrives
   - switchSession loads cached messages instantly from Room before
     the REST call returns — no more blank screen while loading
   - Session resume also loads from cache first
   - Messages survive app kills, process death, and configuration
     changes
   - ChatViewModel changed from ViewModel() to AndroidViewModel(app)
     to access the database context

2. Background notifications (foreground service):
   - ChatNotificationService keeps the WebSocket alive while the app
     is backgrounded and posts a high-priority notification when a
     MessageComplete or ClarifyRequest event arrives while the app
     is not in the foreground
   - Lifecycle wired via LifecycleEventObserver in ChatScreen:
     ON_STOP starts the service, ON_START stops it
   - Tapping the notification returns to the chat
   - New permissions: POST_NOTIFICATIONS, FOREGROUND_SERVICE,
     FOREGROUND_SERVICE_DATA_SYNC

Build changes:
   - Added Room 2.7.1 + KSP to version catalog
   - Added WorkManager 2.10.0 (reserved for future polling fallback)
   - Updated ChatViewModelTest to mock HermesDatabase + use
     AndroidViewModel constructor

* fix(build): use KSP 2.3.9 (new versioning scheme for Kotlin 2.3.x)

* fix(build): add Room schemaDirectory (required by Room Gradle plugin)

* fix(compile): add else branch to WsEvent when expression (exhaustiveness)

* ci(release): add release workflow + R8 minification + proguard rules

New .github/workflows/release.yml:
- Triggers on tag pushes (v*) and manual workflow_dispatch
- Runs full CI (ktlint + lint + test) before building
- Builds assembleRelease with version injection from tag
- Creates a GitHub Release with auto-generated changelog
- Attaches the release APK to the release

Build changes:
- Release builds now use R8 minification (isMinifyEnabled=true)
  and resource shrinking (isShrinkResources=true) for smaller APKs
- versionCode/versionName injectable via -PversionCode / -PversionName
  Gradle properties (passed by CI from the git tag)
- Local dev builds default to versionCode=1, versionName=1.0-dev

ProGuard rules:
- Keep all data model classes (Gson reflection)
- Keep Room entities and RoomDatabase subclasses
- Keep OkHttp/Retrofit interface methods
- Suppress warnings for Compose, Security Crypto, Coroutines

* feat(ci): release workflow + proguard rules + test fix

Release workflow (.github/workflows/release.yml):
  - Triggers on tag push (v*) or manual workflow_dispatch
  - Two jobs: ci (ktlint+lint+test) → build-release
  - Builds a minified, shrunk release APK with version from tag
  - Creates a GitHub Release with auto-generated release notes
  - Attaches the APK as a release asset

Build config:
  - versionCode/versionName now injected from CI via -P flags
  - Release build enables isMinifyEnabled + isShrinkResources
  - proguard-rules.pro: keep rules for Gson models, Room entities,
    OkHttp/Retrofit interfaces, Coroutines, Compose, BuildConfig

Test fix:
  - ChatViewModelTest: use coEvery for suspend DAO methods instead
    of every (compile error — suspend functions need coEvery)
  - Added stubs for all suspend DAO methods used by the ViewModel

---------

Co-authored-by: M57 <hy4ri@users.noreply.github.com>

gradle/libs.versions.toml

@@ -13,6 +13,7 @@ junit = "4.13.2"
 junit5 = "5.11.4"
 junitPlatform = "1.11.4"
 kotlin = "2.3.20"
+ksp = "2.3.9"
 nav3Core = "1.0.1"
 lifecycleViewmodelNav3 = "2.10.0"
 okhttp = "4.12.0"
@@ -20,6 +21,8 @@ retrofit = "2.11.0"
 gson = "2.11.0"
 securityCrypto = "1.1.0-alpha06"
 mockk = "1.13.12"
+room = "2.7.1"
+workManager = "2.10.0"
 
 [libraries]
 androidx-core-ktx = { module = "androidx.core:core-ktx", version.ref = "androidxCore" }
@@ -61,7 +64,17 @@ gson = { module = "com.google.code.gson:gson", version.ref = "gson" }
 # Security
 androidx-security-crypto = { module = "androidx.security:security-crypto", version.ref = "securityCrypto" }
 
+# Database (Room)
+androidx-room-runtime = { module = "androidx.room:room-runtime", version.ref = "room" }
+androidx-room-compiler = { module = "androidx.room:room-compiler", version.ref = "room" }
+androidx-room-ktx = { module = "androidx.room:room-ktx", version.ref = "room" }
+
+# Background notifications (WorkManager)
+androidx-work-runtime = { module = "androidx.work:work-runtime-ktx", version.ref = "workManager" }
+
 [plugins]
 android-application = { id = "com.android.application", version.ref = "androidGradlePlugin" }
 compose-compiler = { id = "org.jetbrains.kotlin.plugin.compose", version.ref = "kotlin" }
-kotlin-serialization = { id = "org.jetbrains.kotlin.plugin.serialization", version.ref = "kotlin" }
+kotlin-serialization = { id = "org.jetbrains.kotlin.plugin.serialization", version.ref = "kotlin" }
+room = { id = "androidx.room", version.ref = "room" }
+ksp = { id = "com.google.devtools.ksp", version.ref = "ksp" }