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/domain/sync/SyncEngine.kt

@@ -24,6 +24,8 @@ import kotlinx.coroutines.sync.withPermit
 import timber.log.Timber
 import java.io.File
 import java.time.Instant
+import java.util.concurrent.atomic.AtomicInteger
+import java.util.concurrent.atomic.AtomicLong
 import javax.inject.Inject
 
 class SyncEngine @Inject constructor(
@@ -33,24 +35,28 @@ class SyncEngine @Inject constructor(
     private val eventDao: SyncEventDao,
     @ApplicationContext private val context: Context,
 ) {
-    suspend fun sync(pair: SyncPair, provider: CloudProvider): SyncResult {
+    suspend fun sync(
+        pair: SyncPair,
+        provider: CloudProvider,
+        onProgress: (suspend (uploaded: Int, downloaded: Int, deleted: Int, bytesTransferred: Long) -> Unit)? = null,
+    ): SyncResult {
         syncPairDao.updateStatus(pair.id, SyncStatus.SYNCING)
         logEvent(pair.id, SyncEventType.SYNC_STARTED, null, null, 0)
 
         return try {
-            val result = performSync(pair, provider)
+            val result = performSync(pair, provider, onProgress = onProgress)
             val finalStatus = when {
                 result.failedFiles > 0 && result.conflicts > 0 -> SyncStatus.CONFLICT
                 result.failedFiles > 0 -> SyncStatus.PARTIAL
                 result.conflicts > 0 -> SyncStatus.CONFLICT
                 else -> SyncStatus.SUCCESS
             }
-            syncPairDao.updateSyncResult(pair.id, Instant.now(), finalStatus, result.conflicts)
+            syncPairDao.updateSyncResult(pair.id, Instant.now(), finalStatus, result.conflicts, result.uploaded, result.downloaded, result.deleted, result.bytesTransferred)
             logEvent(pair.id, SyncEventType.SYNC_COMPLETED, null, "↑${result.uploaded} ↓${result.downloaded} ✕${result.deleted} ✗${result.failedFiles}", result.bytesTransferred)
             result
         } catch (e: Exception) {
             Timber.e(e, "Sync failed for pair ${pair.id}")
-            syncPairDao.updateSyncResult(pair.id, Instant.now(), SyncStatus.FAILED, 0)
+            syncPairDao.updateSyncResult(pair.id, Instant.now(), SyncStatus.FAILED, 0, 0, 0, 0, 0L)
             logEvent(pair.id, SyncEventType.SYNC_FAILED, null, e.message, 0)
             SyncResult(failedFiles = 1, error = e)
         }
@@ -66,6 +72,7 @@ class SyncEngine @Inject constructor(
         pair: SyncPair,
         provider: CloudProvider,
         isRetry: Boolean = false,
+        onProgress: (suspend (Int, Int, Int, Long) -> Unit)? = null,
     ): SyncResult {
         val accessor = makeAccessor(pair.localPath)
         var knownStates = fileStateDao.getForPair(pair.id).associateBy { it.relativePath }
@@ -81,12 +88,16 @@ class SyncEngine @Inject constructor(
             knownStates.keys.none { it in localFiles }) {
             Timber.w("SyncEngine: stale folder states detected for pair ${pair.id} — resetting")
             fileStateDao.deleteForPair(pair.id)
-            return performSync(pair, provider, isRetry = true)
+            return performSync(pair, provider, isRetry = true, onProgress = onProgress)
         }
 
         val allPaths = (localFiles.keys + remoteFiles.keys + knownStates.keys).toSet()
         val hasPriorSyncState = knownStates.isNotEmpty()
         val semaphore = Semaphore(4)
+        val uploadedAtomic = AtomicInteger(0)
+        val downloadedAtomic = AtomicInteger(0)
+        val deletedAtomic = AtomicInteger(0)
+        val bytesAtomic = AtomicLong(0L)
 
         // Each async block returns its outcome; no shared mutable state across coroutines.
         data class FileOutcome(
@@ -119,6 +130,9 @@ class SyncEngine @Inject constructor(
                                     return@withPermit FileOutcome(failed = 1)
                                 }
                                 logEvent(pair.id, SyncEventType.FILE_UPLOADED, rel, null, bytes)
+                                val up = uploadedAtomic.incrementAndGet()
+                                bytesAtomic.addAndGet(bytes)
+                                onProgress?.invoke(up, downloadedAtomic.get(), deletedAtomic.get(), bytesAtomic.get())
                                 // Don't store remote metadata from upload response — the server (Nextcloud etc.)
                                 // may change mtime/etag during post-upload processing. Leaving remoteModifiedAt
                                 // null forces the SKIP reconciliation on the next sync to fill it in from the
@@ -142,6 +156,9 @@ class SyncEngine @Inject constructor(
                                     .getOrDefault(System.currentTimeMillis()).takeIf { it > 0L }
                                     ?: System.currentTimeMillis()
                                 logEvent(pair.id, SyncEventType.FILE_DOWNLOADED, rel, null, bytes)
+                                val down = downloadedAtomic.incrementAndGet()
+                                bytesAtomic.addAndGet(bytes)
+                                onProgress?.invoke(uploadedAtomic.get(), down, deletedAtomic.get(), bytesAtomic.get())
                                 FileOutcome(downloaded = 1, bytesTransferred = bytes,
                                     newState = buildState(pair.id, rel,
                                         LocalFileInfo(rel, remote!!.sizeBytes, localMtime),
@@ -153,6 +170,8 @@ class SyncEngine @Inject constructor(
                                 if (!deleted) Timber.w("SyncEngine: DELETE_LOCAL failed (silent) for $rel")
                                 fileStateDao.delete(pair.id, rel)
                                 logEvent(pair.id, SyncEventType.FILE_DELETED, rel, "local", 0)
+                                val del = deletedAtomic.incrementAndGet()
+                                onProgress?.invoke(uploadedAtomic.get(), downloadedAtomic.get(), del, bytesAtomic.get())
                                 FileOutcome(deleted = 1)
                             }
                             SyncDecision.DELETE_REMOTE -> {
@@ -170,6 +189,8 @@ class SyncEngine @Inject constructor(
                                     fileStateDao.delete(pair.id, rel)
                                     logEvent(pair.id, SyncEventType.FILE_DELETED, rel, "remote", 0)
                                 }
+                                val del = deletedAtomic.incrementAndGet()
+                                onProgress?.invoke(uploadedAtomic.get(), downloadedAtomic.get(), del, bytesAtomic.get())
                                 FileOutcome(deleted = 1)
                             }
                             SyncDecision.CONFLICT -> {