feat(feishu): add Feishu inbound webhook, /gh commands and card actions

- add feishu_links D1 table and link store helpers
- implement X-Lark-Signature verification, url_verification, /gh login|logout|comment|merge|close and card.action.trigger Merge/Close
- render interactive cards with clickable title link, inline links and callback buttons (no whole-card card_link)
- bind Feishu account in OAuth callback
- document event subscription and required scopes

server/lib/core/dispatch.ts

@@ -192,9 +192,11 @@ export async function dispatchEvent(
           ? target.topicId
             ? `${target.chatId}/${target.topicId}`
             : (target.chatId ?? "")
-          : target.threadId
-            ? `${target.channelId}/${target.threadId}`
-            : (target.channelId ?? "");
+          : target.platform === "feishu"
+            ? (target.chatId ?? "")
+            : target.threadId
+              ? `${target.channelId}/${target.threadId}`
+              : (target.channelId ?? "");
 
       const base: {
         ts: number;