fix(native-worker): keep batches and retries intact across seam races

- Verification challenge no longer abandons the batch: batch mates the
  worker cancel would mark skipped are requeued and fenced from later
  snapshot applications, and the adoption loop restarts the queue for
  requeued items when the run ends
- Pause vs cancel race: a cancelled result with no pause flag set waits
  up to 1.5s for the pause intent to land on the main looper before
  being classified as a permanent skip
- Stale Go cancel flag: new ResetDownloadCancel export (wired through
  Android and iOS bridges) drops a pre-registered cancel with no active
  download; retryItem/retryAllFailed call it so the first retry of a
  cancelled-before-start item no longer aborts instantly
- Reconcile-loop errors now cancel the native worker and clear the run
  id before marking items failed, instead of leaving the service
  downloading a batch the UI already wrote off

android/app/src/main/kotlin/com/zarz/spotiflac/DownloadService.kt

@@ -755,6 +755,27 @@ class DownloadService : Service() {
                         writeNativeAlbumReplayGainIfComplete()
                     } else {
                         val errorType = result.optString("error_type")
+                        if (errorType == "cancelled" &&
+                            !nativeWorkerPaused &&
+                            !nativeWorkerCancelRequested &&
+                            generation == nativeWorkerGeneration
+                        ) {
+                            // A pause from Dart cancels the in-flight Go
+                            // download directly but delivers the pause flag
+                            // via a startService intent through the main
+                            // looper; the download can unwind first. Give the
+                            // flag a moment to settle before classifying this
+                            // cancellation as a permanent skip.
+                            var waitedMs = 0L
+                            while (waitedMs < 1500 &&
+                                !nativeWorkerPaused &&
+                                !nativeWorkerCancelRequested &&
+                                generation == nativeWorkerGeneration
+                            ) {
+                                delay(100)
+                                waitedMs += 100
+                            }
+                        }
                         if (errorType == "cancelled" && nativeWorkerPaused && !nativeWorkerCancelRequested) {
                             updateNativeWorkerItem(request.itemId) {
                                 it.status = "queued"

android/app/src/main/kotlin/com/zarz/spotiflac/MainActivity.kt

@@ -2308,6 +2308,13 @@ class MainActivity: FlutterFragmentActivity() {
                             }
                             result.success(null)
                         }
+                        "resetDownloadCancel" -> {
+                            val itemId = call.argument<String>("item_id") ?: ""
+                            withContext(Dispatchers.IO) {
+                                Gobackend.resetDownloadCancel(itemId)
+                            }
+                            result.success(null)
+                        }
                         "setDownloadDirectory" -> {
                             val path = call.argument<String>("path") ?: ""
                             withContext(Dispatchers.IO) {