VoiceSentinel: race in report buffer cleanup can corrupt transcripts and fill disk

VoiceSentinel is a real-time voice moderation system for Minecraft servers. From 2.2.1 until 3.3.1, the optional report buffer feature has a race between retention cleanup and normal transcript writes. In report_buffer.py, _maybe_cleanup() uses an unlocked dictionary for once-per-hour cleanup throttling, allowing simultaneous _cleanup_tenant() operations for one tenant. Cleanup reads transcripts.jsonl and rewrites it in place without file locking or atomic replacement, while report_buffer_append_async uses asyncio.to_thread to append without synchronization. In main.py, concurrent _processing_worker tasks make this reachable in normal operation; processing.worker_count of two or more and public-pool servers sharing a server_key increase collisions. With report_buffer.enabled set to true, racing writes can lose, duplicate or corrupt transcript data and defeat report_buffer.retention_seconds pruning, allowing unbounded disk growth that can exhaust storage and crash the host or other services sharing it. The feature is opt-in and disabled by default. This issue is fixed in version 3.3.1.