Add incoming message queue for Telegram bot

Batches incoming messages by chat_id with a 3-second sliding window
before processing. This prevents confusion when messages arrive
simultaneously from different chats.

- New IncomingQueue module with STM-based in-memory queue
- Messages enqueued immediately, offset acked on enqueue
- 200ms tick loop flushes batches past deadline
- Batch formatting: numbered messages, sender attribution for groups,
  media stubs, reply context
- Media from first message in batch still gets full processing

0 files changed, 0 insertions, 0 deletions