* fix(feishu): add early event-level dedup to prevent duplicate replies
Add synchronous in-memory dedup at EventDispatcher handler level using
message_id as key with 5-minute TTL and 2000-entry cap.
This catches duplicate events immediately when they arrive from the Lark
SDK — before the inbound debouncer or processing queue — preventing the
race condition where two concurrent dispatches enter the pipeline before
either records the messageId in the downstream dedup layer.
Fixes the root cause reported in #42687.
* fix(feishu): correct inverted dedup condition
check() returns false on first call (new key) and true on subsequent
calls (duplicate). The previous `!check()` guard was inverted —
dropping every first delivery and passing all duplicates.
Remove the negation so the guard correctly drops duplicates.
* fix(feishu): simplify eventDedup key — drop redundant accountId prefix
eventDedup is already scoped per account (one instance per
registerEventHandlers call), so the accountId prefix in the cache key
is redundant. Use `evt:${messageId}` instead.
* fix(feishu): share inbound processing claim dedupe
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Co-authored-by: Tak Hoffman <781889+Takhoffman@users.noreply.github.com>