Survive IMDb unique conflicts during movie matching, log per-file sync errors, add library lookup diagnostic, and ship upgrade-node.sh plus Admin upgrade button for Unraid/Synology nodes still on 1.2.9.
Large libraries (~30k files) overflowed a single WS message; sync now runs in ACK'd batches with event buffering on the node.
Co-authored-by: Cursor <cursoragent@cursor.com>