Adapted from MikaelKW/nodecast-tv-plus commit 55cb8de23a37eb5683459bffed9b64c6c5dd73ae. Queue reads, validations, and writes together; return write errors to callers; preserve existing IDs and metadata; route source/user edits through the atomic operations. Cover concurrent writes, stale edits, queue recovery, and administrator races. Co-authored-by: Mikael <mikaelkwessel@gmail.com>