fix: isolate WeChat runtime delivery path

wechat-mp.test.mjs

@@ -333,6 +333,94 @@ test('Page Data requests always rotate away from an existing WeChat route', () =
   assert.equal(shouldForceNewWechatAgentSession({ kind: 'chat.general' }, '换新会话'), true);
 });
 
+test('WeChat session reset acknowledges without sending the control text to Agent', async () => {
+  const token = 'token';
+  const timestamp = '1710000000';
+  const nonce = 'nonce';
+  const sentPayloads = [];
+  const finishedMessages = [];
+  let activeRoute = { agentSessionId: 'session-old' };
+  let startedSessions = 0;
+  let agentReplies = 0;
+  const sessionOrigins = [];
+
+  const service = createBoundWechatService({
+    token,
+    startAgentSession: async (input) => {
+      startedSessions += 1;
+      assert.equal(input.origin, 'wechat');
+      return { id: 'session-new' };
+    },
+    userAuth: {
+      async getWechatAgentRoute() {
+        return activeRoute;
+      },
+      async clearWechatAgentRoute() {
+        activeRoute = null;
+      },
+      async upsertWechatAgentRoute({ agentSessionId }) {
+        activeRoute = { agentSessionId };
+      },
+      async setSessionOrigin(sessionId, origin) {
+        sessionOrigins.push({ sessionId, origin });
+      },
+      async finishWechatMpMessage(input) {
+        finishedMessages.push(input);
+      },
+    },
+    sessionApiFetch: async (_sessionId, pathname) => {
+      if (pathname.includes('/reply')) {
+        agentReplies += 1;
+        throw new Error('session reset must not reach Agent');
+      }
+      return new Response('{}', {
+        status: 200,
+        headers: { 'Content-Type': 'application/json' },
+      });
+    },
+    wechatFetch: async (url, init = {}) => {
+      if (String(url).includes('/cgi-bin/stable_token')) {
+        return new Response(JSON.stringify({
+          access_token: 'access-1',
+          expires_in: 7200,
+        }), {
+          status: 200,
+          headers: { 'Content-Type': 'application/json' },
+        });
+      }
+      if (String(url).includes('/cgi-bin/message/custom/send')) {
+        sentPayloads.push(JSON.parse(init.body));
+        return new Response(JSON.stringify({ errcode: 0, errmsg: 'ok' }), {
+          status: 200,
+          headers: { 'Content-Type': 'application/json' },
+        });
+      }
+      throw new Error(`unexpected wechat url: ${url}`);
+    },
+  });
+
+  const result = await service.handleInboundMessage(
+    inboundXml({ content: '新会话' }),
+    {
+      timestamp,
+      nonce,
+      signature: signatureFor(token, timestamp, nonce),
+    },
+  );
+  await result.task;
+
+  assert.equal(startedSessions, 1);
+  assert.equal(agentReplies, 0);
+  assert.equal(activeRoute?.agentSessionId, 'session-new');
+  assert.deepEqual(sessionOrigins, [{
+    sessionId: 'session-new',
+    origin: 'wechat',
+  }]);
+  assert.match(sentPayloads[0]?.text?.content ?? '', /已切换到新会话/);
+  assert.equal(finishedMessages.at(-1)?.status, 'done');
+  assert.equal(finishedMessages.at(-1)?.agentSessionId, 'session-new');
+});
+
 test('WeChat Page Data repair intent receives the guarded repair workflow', () => {
   assert.equal(isWechatPageDataTask('提交失败，数据没有保存成功'), true);
   assert.equal(isWechatPageDataTask('修复问卷的 Page Data 绑定'), true);