feat(context-enhancement): 新增 chatId 与 threadId 来源字段 (#128)

Add chatId and threadId source fields across all nine IM channels, update UI/docs/tests, reconcile the latest main branch, and credit @Chan-0312 as a contributor.

src/channels/weixin/weixin-bridge.mjs

@@ -786,6 +786,7 @@ export class WeixinHarnessBridge {
           content = enhanceContextContent(originalContent, snapshot, () => ({
             channel: 'weixin',
             senderId: sender,
+            chatId: sender,
           }));
           contextEnhanced = content !== originalContent;
         }