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.

extensions/feishu/src/monitor.account.ts

@@ -402,7 +402,7 @@ function registerEventHandlers(
       const messageId = event.message?.message_id?.trim();
       if (messageId) {
         const eventKey = `${accountId}:evt:${messageId}`;
-        if (!eventDedup.check(eventKey)) {
+        if (eventDedup.check(eventKey)) {
           log(`feishu[${accountId}]: dropping duplicate event for message ${messageId}`);
           return;
         }