[PBI] Ingestion Worker - UDP Receiver and Sequence Tracking

[jinseisieko]

Description & Context

Implement the high-load UDP entry point using asyncio DatagramProtocol with MTU validation (< 1400 bytes) and Graceful Shutdown. Implement sequence tracking logic in Redis, including a reset detector (Threshold > 1,000,000). Update last_activity_at (only if len(packets)>0), execute HINCRBY dropped_delta, and enforce a 6-second TTL on state keys.

Acceptance Criteria

AC 2

• Given a sequence number jump > 1,000,000, When processed, Then a sequence reset is detected and handled correctly.

AC 3

• Given packets are received, When state is updated, Then last_activity_at and dropped_delta are updated in Redis with a strict 6s TTL.

Assigned Reviewer

@Minnezing