Detailed 7-stage plan covering: RPC timeouts under the global throttle gate,
background worker task_done/queue fixes, atomic large-video downloads,
FloodWait-to-429 mapping, FileResponse migration, event-loop hygiene for feed
rendering, SQLite write batching, and a lightweight /ping healthcheck.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Add queue-based background download system to improve performance and reliability:
- Introduce DOWNLOAD_SEMAPHORE to limit concurrent downloads to 3
- Add asyncio.Queue (maxsize 100) with dedicated worker for background processing
- Implement safe_get_messages and safe_download_media wrappers with timeout protection (30s and 120s)
- Add retry logic for KeyError auth failures with 5s backoff
- Replace synchronous sequential downloads with asynchronous queued processing
- Prevent event loop blocking by queuing files instead of immediate download
vvzvlad