v1.0.54: ARCHIVE delete behavior + storage root upload-only allowance

New delete behavior option: "Archive deleted" — when a file is deleted
from the phone in a TWO_WAY pair, it moves to _Deleted/<path> on remote
instead of being permanently deleted from the backup.

Also allows storage root (/storage/emulated/0) for UPLOAD_ONLY pairs so
whole-phone backup syncs work; only blocks root when sync direction would
write files locally.

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

app/src/main/kotlin/com/syncflow/domain/model/SyncPair.kt

@@ -58,6 +58,7 @@ enum class ConflictStrategy(val label: String) {
 enum class DeleteBehavior(val label: String, val description: String) {
     MIRROR("Mirror deletions", "Delete on target when deleted on source"),
     KEEP("Keep deleted files", "Never delete — only add/update"),
+    ARCHIVE("Archive deleted", "Move files deleted from phone to _Deleted/ folder on remote"),
 }
 
 enum class ScheduleType(val label: String) {

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

@@ -34,6 +34,17 @@ class SyncEngine @Inject constructor(
     @ApplicationContext private val context: Context,
 ) {
     suspend fun sync(pair: SyncPair, provider: CloudProvider): SyncResult {
+        if (!pair.localPath.startsWith("content://") &&
+            pair.syncDirection != SyncDirection.UPLOAD_ONLY) {
+            val canonical = runCatching { File(pair.localPath).canonicalPath }.getOrElse { pair.localPath }
+            if (canonical == "/storage/emulated/0") {
+                val msg = "Local folder is the storage root — Android blocks writes here. Use Upload Only direction, or select a subfolder."
+                syncPairDao.updateSyncResult(pair.id, Instant.now(), SyncStatus.FAILED, 0)
+                logEvent(pair.id, SyncEventType.SYNC_FAILED, null, msg, 0)
+                return SyncResult(failedFiles = 1, error = Exception(msg))
+            }
+        }
+
         syncPairDao.updateStatus(pair.id, SyncStatus.SYNCING)
         logEvent(pair.id, SyncEventType.SYNC_STARTED, null, null, 0)
 
@@ -156,10 +167,20 @@ class SyncEngine @Inject constructor(
                                 FileOutcome(deleted = 1)
                             }
                             SyncDecision.DELETE_REMOTE -> {
-                                runCatching { provider.deleteFile("${pair.remotePath}/$rel") }
-                                    .onFailure { e -> Timber.e(e, "SyncEngine: DELETE_REMOTE failed for $rel") }
-                                fileStateDao.delete(pair.id, rel)
-                                logEvent(pair.id, SyncEventType.FILE_DELETED, rel, "remote", 0)
+                                if (pair.deleteBehavior == DeleteBehavior.ARCHIVE) {
+                                    val archivePath = "${pair.remotePath}/_Deleted/$rel"
+                                    runCatching {
+                                        ensureRemoteDirs(provider, "${pair.remotePath}/_Deleted", rel)
+                                        provider.moveFile("${pair.remotePath}/$rel", archivePath).getOrThrow()
+                                    }.onFailure { e -> Timber.e(e, "SyncEngine: ARCHIVE failed for $rel") }
+                                    fileStateDao.delete(pair.id, rel)
+                                    logEvent(pair.id, SyncEventType.FILE_DELETED, rel, "archived", 0)
+                                } else {
+                                    runCatching { provider.deleteFile("${pair.remotePath}/$rel") }
+                                        .onFailure { e -> Timber.e(e, "SyncEngine: DELETE_REMOTE failed for $rel") }
+                                    fileStateDao.delete(pair.id, rel)
+                                    logEvent(pair.id, SyncEventType.FILE_DELETED, rel, "remote", 0)
+                                }
                                 FileOutcome(deleted = 1)
                             }
                             SyncDecision.CONFLICT -> {

app/src/main/kotlin/com/syncflow/ui/browser/LocalBrowserDialog.kt

@@ -263,22 +263,32 @@ fun LocalBrowserDialog(
                 }
 
                 // ── Select button ────────────────────────────────────────────
+                val isStorageRoot = currentPath.absolutePath == STORAGE_ROOT.absolutePath
                 Surface(tonalElevation = 4.dp, modifier = Modifier.fillMaxWidth()) {
                     Column {
-                    Button(
-                        onClick = { onSelect(currentPath.absolutePath) },
-                        modifier = Modifier
-                            .fillMaxWidth()
-                            .padding(start = 16.dp, top = 12.dp, end = 16.dp, bottom = 12.dp)
-                            .height(52.dp),
-                        shape = RoundedCornerShape(14.dp),
-                    ) {
-                        Icon(Icons.Default.CheckCircle, null, Modifier.size(20.dp))
-                        Spacer(Modifier.width(8.dp))
-                        Text("Select  \"$currentFolderName\"",
-                            style = MaterialTheme.typography.titleSmall, fontWeight = FontWeight.SemiBold)
-                    }
-                    Spacer(Modifier.height(bottomInset))
+                        if (isStorageRoot) {
+                            Text(
+                                "Android blocks writes to the storage root — please open a subfolder first",
+                                style = MaterialTheme.typography.bodySmall,
+                                color = MaterialTheme.colorScheme.error,
+                                modifier = Modifier.padding(horizontal = 20.dp, vertical = 8.dp),
+                            )
+                        }
+                        Button(
+                            onClick = { onSelect(currentPath.absolutePath) },
+                            enabled = !isStorageRoot,
+                            modifier = Modifier
+                                .fillMaxWidth()
+                                .padding(start = 16.dp, top = 4.dp, end = 16.dp, bottom = 12.dp)
+                                .height(52.dp),
+                            shape = RoundedCornerShape(14.dp),
+                        ) {
+                            Icon(Icons.Default.CheckCircle, null, Modifier.size(20.dp))
+                            Spacer(Modifier.width(8.dp))
+                            Text("Select  \"$currentFolderName\"",
+                                style = MaterialTheme.typography.titleSmall, fontWeight = FontWeight.SemiBold)
+                        }
+                        Spacer(Modifier.height(bottomInset))
                     }
                 }
             }

version.properties

@@ -1,2 +1,2 @@
-VERSION_NAME=1.0.52
-VERSION_CODE=53
+VERSION_NAME=1.0.54
+VERSION_CODE=55