feat(android-terminal): Phase A — core infrastructure

Foundation work for the Android tablet POS app. Adds the singletons that
every screen needs (config persistence, network awareness, auth) without
touching the existing screen stubs yet — Phases B–F will build on these.

- gradle: bcrypt 0.10.2 pinned (used in Phase C for offline PIN verify)
- LoyaltyApi: + GET /api/v1/store/loyalty/categories endpoint
- ApiModels: + category_ids on StampRequest / PointsEarnRequest,
  + CategoryItem / CategoryListResponse
- DeviceConfigRepository: DataStore wrapper for the paired-tablet state
  (api_url, auth_token, store_id/code/name, cached program/pins/categories
  JSON, per-seller language, resetDevice())
- AuthInterceptor: rewrites every request's host to the paired api_url
  and adds Bearer auth — Retrofit keeps a placeholder baseUrl since the
  real URL only exists post-pair
- NetworkMonitor: Flow<Boolean> isOnline from ConnectivityManager
- StaffPinRepository / CategoryRepository: cache-or-refresh pattern,
  Moshi-serialized to DataStore
- AppModule: wires AuthInterceptor before the logging interceptor
- strings.xml: ~50 strings × 4 locales (en authoritative; fr/de/lb
  translated, mirroring the loyalty backend's i18n approach)

Verified by ./gradlew assembleDebug — clean build, only pre-existing
warnings (Theme statusBarColor deprecation, Moshi-kapt deprecation).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

clients/terminal-android/app/build.gradle.kts

@@ -101,6 +101,9 @@ dependencies {
     // DataStore (device config persistence)
     implementation(libs.datastore.preferences)
 
+    // bcrypt (verify staff PIN hashes locally — pure Java, no native deps)
+    implementation(libs.bcrypt)
+
     // Testing
     testImplementation(libs.junit)
     androidTestImplementation(libs.junit.android)