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>

session-stream.test.mjs

@@ -0,0 +1,46 @@
+import assert from 'node:assert/strict';
+import test from 'node:test';
+import {
+  formatSessionStreamSseChunk,
+  isSessionStreamReplayEnabled,
+  isTerminalSessionEvent,
+  parseSessionSseBlock,
+  parseSessionStreamLastEventId,
+  shouldPersistSessionStreamEvent,
+  shouldSkipUpstreamAfterSessionReplay,
+} from './session-stream.mjs';
+
+test('formatSessionStreamSseChunk includes id for replay cursor', () => {
+  const chunk = formatSessionStreamSseChunk({
+    id: 'evt-1',
+    data: { type: 'Message', message: { role: 'assistant' } },
+  });
+  assert.match(chunk, /^id: evt-1\n/);
+  assert.match(chunk, /"type":"Message"/);
+});
+
+test('parseSessionSseBlock extracts id and data', () => {
+  const parsed = parseSessionSseBlock('id: upstream-1\ndata: {"type":"Finish"}\n\n');
+  assert.equal(parsed.id, 'upstream-1');
+  assert.equal(parsed.data, '{"type":"Finish"}');
+});
+
+test('terminal detection and upstream skip policy', () => {
+  assert.equal(isTerminalSessionEvent({ type: 'Finish' }), true);
+  assert.equal(isTerminalSessionEvent({ type: 'Message' }), false);
+  assert.equal(
+    shouldSkipUpstreamAfterSessionReplay([
+      { payload: { type: 'Message' } },
+      { payload: { type: 'Finish' } },
+    ]),
+    true,
+  );
+  assert.equal(
+    shouldSkipUpstreamAfterSessionReplay([{ payload: { type: 'Message' } }]),
+    false,
+  );
+  assert.equal(shouldPersistSessionStreamEvent({ type: 'Ping' }), false);
+  assert.equal(shouldPersistSessionStreamEvent({ type: 'Message' }), true);
+  assert.equal(isSessionStreamReplayEnabled({ MEMIND_SESSION_STREAM_REPLAY: '1' }), true);
+  assert.equal(parseSessionStreamLastEventId(' abc '), 'abc');
+});