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>

app/build.gradle.kts

@@ -4,6 +4,8 @@ plugins {
   alias(libs.plugins.android.application)
   alias(libs.plugins.compose.compiler)
   alias(libs.plugins.kotlin.serialization)
+  alias(libs.plugins.room)
+  alias(libs.plugins.ksp)
 }
 
 android {
@@ -13,13 +15,16 @@ android {
         applicationId = "com.m57.hermescontrol"
         minSdk = 26
         targetSdk = 36
-        versionCode = 1
-        versionName = "1.0"
+        // Version overrides passed from CI via -PversionName / -PversionCode
+        // Falls back to defaults for local development.
+        versionCode = (project.findProperty("versionCode") as? String)?.toIntOrNull() ?: 1
+        versionName = (project.findProperty("versionName") as? String) ?: "1.0-dev"
     }
 
     buildTypes {
         release {
-            isMinifyEnabled = false
+            isMinifyEnabled = true
+            isShrinkResources = true
             proguardFiles(getDefaultProguardFile("proguard-android-optimize.txt"), "proguard-rules.pro")
             signingConfig = signingConfigs.getByName("debug")
         }
@@ -46,6 +51,10 @@ kotlin {
     jvmToolchain(17)
 }
 
+room {
+    schemaDirectory("$projectDir/schemas")
+}
+
 dependencies {
   val composeBom = platform(libs.androidx.compose.bom)
   implementation(composeBom)
@@ -82,6 +91,14 @@ dependencies {
   implementation(libs.androidx.security.crypto)
   implementation("androidx.startup:startup-runtime:1.1.1")
 
+  // Local database (Room) — message persistence
+  implementation(libs.androidx.room.runtime)
+  implementation(libs.androidx.room.ktx)
+  ksp(libs.androidx.room.compiler)
+
+  // Background notifications (WorkManager)
+  implementation(libs.androidx.work.runtime)
+
   // Local tests: jUnit, coroutines, Android runner
   testImplementation(libs.junit)
   testImplementation(libs.junit.jupiter.api)