Closes#23369
Feishu may redeliver the same message during WebSocket reconnects or process
restarts. The existing in-memory dedup map is lost on restart, so duplicates
slip through.
This adds a dual-layer dedup strategy:
- Memory cache (fast synchronous path, unchanged capacity)
- Filesystem store (~/.openclaw/feishu/dedup/) that survives restarts
TTL is extended from 30 min to 24 h. Disk writes use atomic rename and
probabilistic cleanup to keep each per-account file under 10 k entries.
Disk errors are caught and logged — message handling falls back to
memory-only behaviour so it is never blocked.
9a8179fd59