fix(browser): 修复 download 事件的 pageIndex 过滤

为 browser_wait_for_event 的 download 路径补齐按页面 frame tree 过滤，避免多页面或动态 iframe 下载时误命中或漏命中。

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

lib/mcp/ccs-browser-server.cjs

@@ -4174,8 +4174,38 @@ async function waitForPageEvent({ page, timeoutMs, event }) {
   });
 }
 
-async function waitForBrowserDownloadEvent(timeoutMs, event) {
-  const targets = await fetchJson(`${getHttpUrl()}/json/list`);
+async function getPageFrameIds(page) {
+  const response = await sendCdpCommand(page, 'Page.getFrameTree', {});
+  const frameTree = response?.frameTree;
+  const frameIds = new Set();
+
+  function visitFrameTree(node) {
+    if (!node || typeof node !== 'object') {
+      return;
+    }
+    const frameId = node.frame?.id;
+    if (typeof frameId === 'string' && frameId) {
+      frameIds.add(frameId);
+    }
+    const childFrames = Array.isArray(node.childFrames) ? node.childFrames : [];
+    for (const childFrame of childFrames) {
+      visitFrameTree(childFrame);
+    }
+  }
+
+  visitFrameTree(frameTree);
+
+  if (frameIds.size === 0) {
+    throw new Error('Browser MCP could not determine the selected page frame IDs.');
+  }
+  return frameIds;
+}
+
+async function waitForBrowserDownloadEvent(page, timeoutMs, event) {
+  const [targets, frameIds] = await Promise.all([
+    fetchJson(`${getHttpUrl()}/json/list`),
+    getPageFrameIds(page),
+  ]);
   const browserTarget = Array.isArray(targets)
     ? targets.find((target) => target && typeof target === 'object' && target.type === 'browser')
     : null;
@@ -4227,6 +4257,16 @@ async function waitForBrowserDownloadEvent(timeoutMs, event) {
         if (message?.method !== 'Browser.downloadWillBegin') {
           return;
         }
+        const eventFrameId = message.params?.frameId;
+        if (!frameIds.has(eventFrameId)) {
+          const refreshedFrameIds = await getPageFrameIds(page);
+          if (!refreshedFrameIds.has(eventFrameId)) {
+            return;
+          }
+          for (const frameId of refreshedFrameIds) {
+            frameIds.add(frameId);
+          }
+        }
         const observed = {
           url: message.params?.url || '',
           suggestedFilename: message.params?.suggestedFilename || '',
@@ -4248,7 +4288,7 @@ async function waitForBrowserDownloadEvent(timeoutMs, event) {
 
 async function waitForMatchingEvent({ page, timeoutMs, event }) {
   if (event.kind === 'download') {
-    return await waitForBrowserDownloadEvent(timeoutMs, event);
+    return await waitForBrowserDownloadEvent(page, timeoutMs, event);
   }
   return await waitForPageEvent({ page, timeoutMs, event });
 }