v0.9.3

Fixed

• Race condition in DatabaseTracker::markChunkUploaded() — concurrent chunk uploads lost writes. The previous implementation read uploaded_chunks from the model, mutated the PHP array in memory, and wrote it back with update() — a classic read-modify-write without locking. With the default client-side concurrency of 3 parallel chunk requests, two workers would read the same pre-state, both append their own index, and the second update() would clobber the first. Symptom: a file with N chunks would end up stuck at is_complete: false with fewer than N indices in uploaded_chunks, and the BatchCompleted broadcast never fired. Fix wraps the read-mutate-write in DB::transaction() + lockForUpdate(), so the row is locked for the duration of the update and writes serialize correctly. Works on MySQL, Postgres, and SQLite (SQLite serializes the transaction at the BEGIN level; set busy_timeout and journal_mode=WAL on the connection if you see database is locked errors under load).

Tests

• DatabaseTrackerTest covers the transactional path and asserts that markChunkUploaded opens a DB transaction.