The Feishu adapter stored one asyncio.Lock per chat_id in a plain dict
with no upper bound, so a long-running gateway that saw many distinct
chats grew _chat_locks without limit. Port the LRU-eviction pattern
already used by the yuanbao adapter: OrderedDict + move_to_end on access,
CHAT_LOCK_MAX_SIZE cap (1000), and eviction that skips currently-held
locks (falling back to dropping the LRU entry only if all are held).
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