feat: 本地 uv 与托管 Python 环境管理

- 新增 uv 管理：只认程序目录副本或指定路径，支持从科大镜像下载并按 sha256 校验

- uv 环境变量（UV_*）可配置，默认相对程序目录（python / uv-cache），同时注入 uv 调用与任务进程

- 新增托管虚拟环境与 Python 版本管理：用 uv 下载解释器、预创建环境、查看已装包

- 新建任务保存时自动创建 .venv，运行期只校验、不再自动装依赖；镜像只在装包时使用

- 前端改为顶部品牌栏 + 三栏工作台，uv / 镜像源 / 虚拟环境各自独立弹窗

- 发布包构建后去掉工作区继承的低完整性标签

- 修复调度集成测试并发时误取 skipped 运行的问题

backend/tests/runs.rs

@@ -201,6 +201,46 @@ async fn wait_for_run(router: &Router, run_id: i64) -> Value {
     panic!("run {run_id} did not reach a terminal state");
 }
 
+#[tokio::test]
+async fn python_task_without_venv_fails_with_editor_hint() {
+    let app = test_app().await;
+    let working_dir = app._temp_dir.path().join("bare-python");
+    fs::create_dir_all(&working_dir).expect("working directory should be created");
+    fs::write(working_dir.join("main.py"), "print('hi')\n").expect("script should be written");
+
+    let mut task = script_task(
+        "bare_python",
+        &working_dir.to_string_lossy(),
+        "python.exe",
+        "main.py",
+        vec![],
+        "0 0 2 * * *",
+        10,
+    );
+    task["action"]["language"] = json!("python");
+    let create_response = send_json(&app.router, Method::POST, "/api/v1/tasks", Some(task)).await;
+    assert_eq!(create_response.status(), StatusCode::CREATED);
+
+    let run_response = send_json(
+        &app.router,
+        Method::POST,
+        "/api/v1/tasks/bare_python/run",
+        None,
+    )
+    .await;
+    assert_eq!(run_response.status(), StatusCode::ACCEPTED);
+    let run = response_json(run_response).await;
+    let completed = wait_for_run(&app.router, run["id"].as_i64().unwrap()).await;
+
+    assert_eq!(completed["status"], "failed");
+    let message = completed["error_message"]
+        .as_str()
+        .expect("failed run should carry an error message");
+    // 运行期不再自动装依赖，只提示去编辑器里创建。
+    assert!(message.contains("编辑器里用 uv 创建"), "{message}");
+    app.state.shutdown();
+}
+
 #[tokio::test]
 async fn shell_language_runs_batch_file_with_cmd_c() {
     let app = test_app().await;
@@ -706,11 +746,12 @@ async fn scheduler_runs_tasks_and_tracks_enable_state() {
         )
         .await;
         let runs = response_json(response).await;
-        if let Some(item) = runs["items"]
-            .as_array()
-            .and_then(|items| items.first())
-            .filter(|item| item["trigger"] == "schedule")
-        {
+        // 每秒触发一次，机器忙时上一轮还没结束，最新一条可能是 skipped；取真正跑起来那条。
+        if let Some(item) = runs["items"].as_array().and_then(|items| {
+            items
+                .iter()
+                .find(|item| item["trigger"] == "schedule" && item["status"] != "skipped")
+        }) {
             scheduled_run = Some(item.clone());
             break;
         }