v1.0.63: live sync progress counters, pause/resume, .gitignore fix

- SyncEngine: accepts onProgress callback — emits uploaded/downloaded/
  deleted/bytes counts atomically as each file completes
- SyncWorker: streams progress to WorkManager data so the UI can poll
  it live; reports per-run counters in the completion notification;
  adds pause/resume support
- HomeViewModel/PairDetailViewModel: subscribe to live WorkManager
  progress and surface it via SyncProgress state
- SyncPairEntity/SyncPairDao/SyncDatabase: persist last-run counters
  (uploaded, downloaded, deleted, bytesTransferred) in the DB with a
  Room migration (v3→v4)
- AppModule: provides WorkManager as an injectable singleton
- .gitignore: add .kotlin/ to exclude compiler session files

Security: no new issues — all logging via Timber (debug-only), DB
queries use Room parameterized API, file sharing via FileProvider.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/src/main/kotlin/com/syncflow/di/AppModule.kt

@@ -22,7 +22,7 @@ object AppModule {
     fun provideDatabase(@ApplicationContext ctx: Context): SyncDatabase =
         Room.databaseBuilder(ctx, SyncDatabase::class.java, "syncflow.db")
             .fallbackToDestructiveMigrationFrom(1)
-            .addMigrations(SyncDatabase.MIGRATION_2_3)
+            .addMigrations(SyncDatabase.MIGRATION_2_3, SyncDatabase.MIGRATION_3_4)
             .build()
 
     @Provides fun provideCloudAccountDao(db: SyncDatabase): CloudAccountDao = db.cloudAccountDao()