[DeckSync] Drop the queued download when a local delete wins

The unmatched-server-rows pass queued a download for every row with no
local file, including rows whose sidecar record is being deleted in the
same run. The delete ran first, so the download then failed with
NameNotFound and the summary reported a clean delete as removed plus
skipped. Cancel the pending download for the deleted row id instead; a
failed delete keeps it, which preserves the restore-the-file fallback.

cockatrice/src/interface/deck_sync/deck_sync_manager.cpp

@@ -762,8 +762,16 @@ void DeckSyncManager::onDeleteFinished(const Response &response,
     if (response.response_code() == Response::RespOk || response.response_code() == Response::RespNameNotFound) {
         DeckSyncSidecar sidecar(sidecarPath);
         sidecar.load();
+        const int deletedDeckId = sidecar.get(relativePath).remoteId;
         sidecar.remove(relativePath);
         sidecar.save();
+        if (deletedDeckId != -1) {
+            // The unmatched-server-rows pass queued a download for this row before
+            // the delete ran. The delete won, so drop the download instead of
+            // letting it fail with NameNotFound and count as a skipped deck. A
+            // failed delete leaves the download in place as the fallback.
+            pendingDownloads.removeIf([deletedDeckId](const DownloadOp &op) { return op.deckId == deletedDeckId; });
+        }
         ++removedCount;
     } else {
         ++skippedCount;