feat: 人工接管任务（takeover）+ 任务详情展示附件

B-③ takeover（⑧ ★ POST /api/tasks/:id/takeover）：

后端：
- POST /api/tasks/:id/takeover：准备（或复用 result.worktree）任务 worktree，
  返回 {taskId, worktree, branch, console}——console 为用户在自己终端起交互式
  claude 的命令（daemon 无 TTY，不在进程内起交互会话）；在途 run 时拒绝

前端：
- api.takeover；TakeoverModal（展示命令 + 一键复制 + 分支提示）
- TaskDetail 加「⌨ 人工接管」按钮（onTakeover 经 TaskSection→TaskRow 线程下来）
- 顺带：TaskDetail 展示任务附件（📎 文件名，读 task._raw.attachments）

验证：typecheck 干净；206 测试通过；前端 build + dev 渲染 0 错误。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/api/server.ts

@@ -9,7 +9,7 @@ import { syncProject, hasTodoJson } from '../sync/todo-sync.js';
 import { resolvedExecutorModels } from '../executor/models.js';
 import { classifyComplexity, type ClassifierFn } from '../executor/classify.js';
 import { mergeBranch } from '../executor/merge.js';
-import { git, removeWorktree } from '../executor/worktree.js';
+import { git, removeWorktree, createWorktree } from '../executor/worktree.js';
 import { cleanupTaskRunArtifacts } from '../executor/cleanup.js';
 import { resolveLogo, LOGO_MIME } from './logo.js';
 import { readTranscript, TranscriptError } from '../executor/transcript.js';
@@ -248,6 +248,24 @@ export function buildServer(opts: ApiOptions): FastifyInstance {
     return { attachments: store.addAttachments(id, saved) };
   });
 
+  // 人工接管：准备（或复用）任务 worktree，返回用户在自己终端起交互式 claude 的命令。
+  // 适用卡住/需人工的任务——人接手手动改。不在 daemon 内起交互会话（无 TTY）。
+  app.post('/api/tasks/:id/takeover', async (req, reply) => {
+    const { id } = req.params as { id: string };
+    const task = store.getTask(id);
+    if (!task) return reply.code(404).send({ error: `任务不存在: ${id}` });
+    if (store.hasInflightRun(id)) return reply.code(400).send({ error: '任务有在途 run，无法接管' });
+    const project = store.getProject(task.projectId);
+    if (!project) return reply.code(404).send({ error: `项目不存在: ${task.projectId}` });
+    let worktree = task.result?.worktree ?? null;
+    let branch = task.result?.branch ?? null;
+    if (!worktree) {
+      const wt = await createWorktree(project.repoPath, id, project.defaultBranch);
+      worktree = wt.dir; branch = wt.branch;
+    }
+    return { taskId: id, worktree, branch, console: `cd ${worktree} && claude` };
+  });
+
   // 部分更新任务（title/priority/complexity；complexity 重置逻辑在 Store.patchTask）
   app.patch('/api/tasks/:id', (req) => {
     const { id } = req.params as { id: string };