fix: make update center state consistent

tests/update-api.test.ts

@@ -155,6 +155,53 @@ describe("更新 API", () => {
     expect(checked.json().latest).toMatchObject({ version: "1.3.0", isNewer: true });
   });
 
+  it("不会应用已经等于当前版本的暂存更新", async () => {
+    const session = await login("update-staged-current");
+    const admin = database.sqlite.prepare("SELECT id FROM admins WHERE username=?").get("update-staged-current") as { id: string };
+    const now = Date.now();
+    const stagedId = randomUUID();
+    database.sqlite.prepare(`
+      INSERT INTO update_jobs(
+        id, admin_id, operation, status, version, platform, release_url,
+        asset_name, asset_url, expected_sha256, actual_sha256, download_path,
+        created_at, updated_at
+      ) VALUES (?, ?, 'download', 'staged', ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+    `).run(
+      stagedId,
+      admin.id,
+      config.appVersion,
+      detectPlatform().target,
+      config.updateMetadataUrl,
+      "current.tar.gz",
+      "https://updates.example/current.tar.gz",
+      "c".repeat(64),
+      "c".repeat(64),
+      path.join(config.dataDir, "staged-current"),
+      now,
+      now,
+    );
+
+    const apply = await app.inject({
+      method: "POST",
+      url: "/api/update/apply",
+      headers: { origin: config.publicOrigin, cookie: session.cookies, "x-csrf-token": session.csrf },
+      payload: { jobId: stagedId, version: config.appVersion, confirm: true },
+    });
+    expect(apply.statusCode).toBe(409);
+    // Reconciliation expires same-version staged jobs before the apply route
+    // can consume them, so the public response is the generic not-staged
+    // conflict while the database records the precise expiry reason.
+    expect(apply.json().error.code).toBe("UPDATE_NOT_STAGED");
+    expect(database.sqlite.prepare("SELECT status, error_message AS errorMessage FROM update_jobs WHERE id=?").get(stagedId)).toEqual({
+      status: "failed",
+      errorMessage: "暂存更新已过期，当前版本无需再次升级",
+    });
+
+    const status = await app.inject({ method: "GET", url: "/api/update/status", headers: { cookie: session.cookies } });
+    expect(status.statusCode).toBe(200);
+    expect(status.json().job).toBeNull();
+  });
+
   it("更新任务只对发起管理员可见，并隐藏内部错误详情", async () => {
     const owner = await login("update-owner");
     const other = await login("update-other");