feat: auto-sync bound codex threads into conversations

tests/device-import-draft.test.ts

@@ -485,3 +485,70 @@ test("device import routes reject unrelated logged-in members", async () => {
   });
   assert.equal(getResponse.status, 403);
 });
+
+test("existing bound production devices auto-sync suggested candidates into conversations on heartbeat", async () => {
+  await setup();
+
+  const heartbeatResponse = await deviceHeartbeatRoute(
+    new NextRequest("http://127.0.0.1:3000/api/device-heartbeat", {
+      method: "POST",
+      headers: { "content-type": "application/json" },
+      body: JSON.stringify({
+        deviceId: "mac-studio",
+        token: "boss-mac-studio-token",
+        name: "Mac Studio",
+        avatar: "M",
+        account: "17600003315",
+        status: "online",
+        quota5h: 68,
+        quota7d: 81,
+        projects: ["Boss 移动控制台", "硬件审计协作"],
+        endpoint: "mac://kris.local",
+        projectCandidates: [
+          {
+            folderName: "yuandi",
+            folderRef: "/Users/kris/code/yuandi",
+            threadId: "session-yuandi-1",
+            threadDisplayName: "Epicurus",
+            codexFolderRef: "/Users/kris/code/yuandi",
+            codexThreadRef: "session-yuandi-1",
+            lastActiveAt: "2026-03-30T12:42:56+08:00",
+            suggestedImport: true,
+          },
+          {
+            folderName: "wenshenapp",
+            folderRef: "/Users/kris/code/wenshenapp",
+            threadId: "session-wenshenapp-1",
+            threadDisplayName: "wenshenapp · ea5f",
+            codexFolderRef: "/Users/kris/code/wenshenapp",
+            codexThreadRef: "session-wenshenapp-1",
+            lastActiveAt: "2026-03-30T12:34:51+08:00",
+            suggestedImport: true,
+          },
+        ],
+      }),
+    }),
+  );
+  assert.equal(heartbeatResponse.status, 200);
+
+  const payload = (await heartbeatResponse.json()) as {
+    importDraft?: { status: string; selectedCandidateIds: string[] } | null;
+  };
+  assert.equal(payload.importDraft?.status, "applied");
+  assert.equal(payload.importDraft?.selectedCandidateIds.length, 2);
+
+  const nextState = await readState();
+  const yuandiProject = nextState.projects.find(
+    (project) => project.threadMeta.codexThreadRef === "session-yuandi-1",
+  );
+  const wenshenProject = nextState.projects.find(
+    (project) => project.threadMeta.codexThreadRef === "session-wenshenapp-1",
+  );
+  assert.ok(yuandiProject, "expected a discovered yuandi session to become a real chat window");
+  assert.ok(wenshenProject, "expected a discovered wenshenapp session to become a real chat window");
+  assert.equal(yuandiProject?.threadMeta.folderName, "yuandi");
+  assert.equal(wenshenProject?.threadMeta.folderName, "wenshenapp");
+
+  const device = nextState.devices.find((item) => item.id === "mac-studio");
+  assert.deepEqual(device?.projects, ["yuandi", "wenshenapp"]);
+});