v1.0.29: fix sync loop, stale-state auto-heal, icon redesign

- SyncEngine: self-healing stale folder state detection (isRetry) wipes
  orphaned SyncFileStateEntity records when localPath changes without a
  pair re-save — prevents repeated DELETE_REMOTE on 32 old files
- SyncEngine: second-precision mtime comparison (/ 1000 / .epochSecond)
  eliminates phantom localChanged=true from FAT32/WebDAV precision mismatch
- FileWatchService: syncCooldownUntil map suppresses FileObserver events
  for 120s after sync starts and 60s after it finishes, breaking the
  download→FileObserver→sync→download feedback loop
- Icon: three bold teardrop shapes (teal/red/amber) rotated 0/120/240°
  on dark charcoal background with white cloud at intersection

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

app/src/main/kotlin/com/syncflow/domain/sync/SyncEngine.kt

@@ -62,13 +62,28 @@ class SyncEngine @Inject constructor(
         else
             LocalAccessor.JavaFile(File(localPath))
 
-    private suspend fun performSync(pair: SyncPair, provider: CloudProvider): SyncResult {
+    private suspend fun performSync(
+        pair: SyncPair,
+        provider: CloudProvider,
+        isRetry: Boolean = false,
+    ): SyncResult {
         val accessor = makeAccessor(pair.localPath)
-        val knownStates = fileStateDao.getForPair(pair.id).associateBy { it.relativePath }
+        var knownStates = fileStateDao.getForPair(pair.id).associateBy { it.relativePath }
         val remoteFiles = provider.listFiles(pair.remotePath).getOrThrow()
             .associateBy { it.path.removePrefix(pair.remotePath).trimStart('/') }
         val localFiles = accessor.walkFiles(pair)
 
+        // Self-healing: if every known-state path is absent from the current local scan but
+        // the local folder does have files, the localPath was changed without clearing state.
+        // The stale records would cause every old file to look like "DELETE_REMOTE" and every
+        // new file to re-upload indefinitely. Wipe and retry once as a fresh initial sync.
+        if (!isRetry && knownStates.isNotEmpty() && localFiles.isNotEmpty() &&
+            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)
+        }
+
         val allPaths = (localFiles.keys + remoteFiles.keys + knownStates.keys).toSet()
         val hasPriorSyncState = knownStates.isNotEmpty()
         val semaphore = Semaphore(4)