fix(extension): include targetId in detach event and forward close to extension

- Add targetId to synthetic Target.detachedFromTarget so Playwright's
  CRBrowser._onDetachedFromTarget can look up the page correctly
- Forward Target.closeTarget to the extension so the actual browser
  tab is removed, keeping browser UI in sync with Playwright state

Author: snomiao

packages/playwright-core/src/tools/mcp/cdpRelay.ts

@@ -344,10 +344,14 @@ export class CDPRelayServer {
         const targetId = params?.targetId;
         const tabSessionId = this._findSessionByTargetId(targetId);
         if (tabSessionId) {
+          const tabId = this._tabSessions.get(tabSessionId)!.tabId;
           this._removeTabSession(tabSessionId);
+          // Forward the close to the extension so the actual browser tab is removed.
+          if (tabId !== undefined)
+            this._extensionConnection?.send('forwardCDPCommand', { tabId, method: 'Target.closeTarget', params }).catch(() => {});
           this._sendToPlaywright({
             method: 'Target.detachedFromTarget',
-            params: { sessionId: tabSessionId },
+            params: { sessionId: tabSessionId, targetId },
           });
         }
         return { success: true };