fix live camera runtime refresh and title recovery

tests/e2e/app.spec.ts

@@ -82,7 +82,23 @@ test("live camera switches into viewer mode when another device already owns ana
   await expect(page.getByTestId("live-camera-score-overall")).toBeVisible();
 });
 
-test("live camera retries viewer stream when owner track is not ready on first attempt", async ({ page }) => {
+test("live camera recovers mojibake viewer titles before rendering", async ({ page }) => {
+  const state = await installAppMocks(page, { authenticated: true, liveViewerMode: true });
+  const mojibakeTitle = Buffer.from("服务端同步烟雾测试", "utf8").toString("latin1");
+  if (state.liveRuntime.runtimeSession) {
+    state.liveRuntime.runtimeSession.title = mojibakeTitle;
+    state.liveRuntime.runtimeSession.snapshot = {
+      ...state.liveRuntime.runtimeSession.snapshot,
+      title: mojibakeTitle,
+    };
+  }
+
+  await page.goto("/live-camera");
+  await expect(page.getByRole("heading", { name: "服务端同步烟雾测试" })).toBeVisible();
+  await expect(page.getByText(mojibakeTitle)).toHaveCount(0);
+});
+
+test("live camera no longer opens viewer peer retries when server relay is active", async ({ page }) => {
   const state = await installAppMocks(page, {
     authenticated: true,
     liveViewerMode: true,
@@ -91,9 +107,9 @@ test("live camera retries viewer stream when owner track is not ready on first a
 
   await page.goto("/live-camera");
   await expect(page.getByText("同步观看模式")).toBeVisible();
-  await expect.poll(() => state.viewerSignalConflictRemaining).toBe(0);
-  await expect.poll(() => state.mediaSession?.viewerCount ?? 0).toBe(1);
-  await expect(page.getByText(/同步观看中|重新同步/).first()).toBeVisible();
+  await expect.poll(() => state.viewerSignalConflictRemaining).toBe(1);
+  await expect.poll(() => state.mediaSession?.viewerCount ?? 0).toBe(0);
+  await expect(page.locator('img[alt="同步中的实时分析画面"]')).toBeVisible();
 });
 
 test("live camera archives overlay videos into the library after analysis stops", async ({ page }) => {

tests/e2e/helpers/mockApp.ts

@@ -866,6 +866,73 @@ export async function installAppMocks(
       return points;
     };
 
+    class FakeVideoTrack {
+      kind = "video";
+      enabled = true;
+      muted = false;
+      readyState = "live";
+      id = "fake-video-track";
+      label = "Fake Camera";
+
+      stop() {}
+
+      getSettings() {
+        return {
+          facingMode: "environment",
+          width: 1280,
+          height: 720,
+          frameRate: 30,
+        };
+      }
+
+      getCapabilities() {
+        return {};
+      }
+
+      async applyConstraints() {
+        return undefined;
+      }
+    }
+
+    class FakeAudioTrack {
+      kind = "audio";
+      enabled = true;
+      muted = false;
+      readyState = "live";
+      id = "fake-audio-track";
+      label = "Fake Mic";
+
+      stop() {}
+
+      getSettings() {
+        return {};
+      }
+
+      getCapabilities() {
+        return {};
+      }
+
+      async applyConstraints() {
+        return undefined;
+      }
+    }
+
+    const createFakeMediaStream = (withAudio = false) => {
+      const videoTrack = new FakeVideoTrack();
+      const audioTrack = withAudio ? new FakeAudioTrack() : null;
+      const tracks = audioTrack ? [videoTrack, audioTrack] : [videoTrack];
+      return {
+        active: true,
+        id: `fake-stream-${Math.random().toString(36).slice(2)}`,
+        getTracks: () => tracks,
+        getVideoTracks: () => [videoTrack],
+        getAudioTracks: () => (audioTrack ? [audioTrack] : []),
+        addTrack: () => undefined,
+        removeTrack: () => undefined,
+        clone: () => createFakeMediaStream(withAudio),
+      } as unknown as MediaStream;
+    };
+
     class FakePose {
       callback = null;
 
@@ -894,9 +961,19 @@ export async function installAppMocks(
       value: async () => undefined,
     });
 
+    Object.defineProperty(HTMLMediaElement.prototype, "srcObject", {
+      configurable: true,
+      get() {
+        return (this as HTMLMediaElement & { __srcObject?: MediaStream }).__srcObject ?? null;
+      },
+      set(value) {
+        (this as HTMLMediaElement & { __srcObject?: MediaStream }).__srcObject = value as MediaStream;
+      },
+    });
+
     Object.defineProperty(HTMLCanvasElement.prototype, "captureStream", {
       configurable: true,
-      value: () => new MediaStream(),
+      value: () => createFakeMediaStream(),
     });
 
     class FakeMediaRecorder extends EventTarget {
@@ -961,7 +1038,7 @@ export async function installAppMocks(
       async setRemoteDescription(description: { type: string; sdp: string }) {
         this.remoteDescription = description;
         this.connectionState = "connected";
-        this.ontrack?.({ streams: [new MediaStream()] });
+        this.ontrack?.({ streams: [createFakeMediaStream()] });
         this.onconnectionstatechange?.();
       }
 
@@ -984,7 +1061,7 @@ export async function installAppMocks(
     Object.defineProperty(navigator, "mediaDevices", {
       configurable: true,
       value: {
-        getUserMedia: async () => new MediaStream(),
+        getUserMedia: async (constraints?: { audio?: unknown }) => createFakeMediaStream(Boolean(constraints?.audio)),
         enumerateDevices: async () => [
           { deviceId: "cam-1", kind: "videoinput", label: "Front Camera", groupId: "g1" },
           { deviceId: "cam-2", kind: "videoinput", label: "Back Camera", groupId: "g1" },