feat(h5): web 联网能力、实时查询路由与 session Finish 对齐

- 新增 web 能力并挂载 platform/web（web_search/fetch_url）
- 实时查询强制 web skill，router fallback 与 await session Finish
- Session Broker 覆盖率/指标、stream replay 与相关单测/E2E 脚本

Co-authored-by: Cursor <cursoragent@cursor.com>

scripts/verify-h5-session-patches.mjs

@@ -16,6 +16,10 @@ const testFiles = [
   'chat-finish-sync.test.mjs',
   'conversation-display.test.mjs',
   'mindspace-h5-html-finish-guard.test.mjs',
+  'session-broker-coverage.test.mjs',
+  'session-stream.test.mjs',
+  'session-stream-store.test.mjs',
+  'session-broker-metrics.test.mjs',
 ];
 
 function run(label, command, args) {
@@ -31,6 +35,7 @@ function run(label, command, args) {
 }
 
 run('unit tests', process.execPath, ['--test', ...testFiles]);
+run('session broker coverage', process.execPath, ['scripts/check-session-broker-coverage.mjs']);
 run('goosed proxy boundary', process.execPath, ['scripts/check-goosed-proxy-boundary.mjs']);
 run('mindspace publish guards', process.execPath, ['scripts/verify-mindspace-publish-guards.mjs']);