fix: simplify task center scopes and status filters

Task Center previously split unbound tasks into a global scope and tasks needing attention into a separate filter. Keep Current project and All projects, label unbound tasks, and restore legacy global scope preferences as all-projects without changing task data.

Keep Active, Paused, and Finished filters. Active includes idle, queued, running, waiting_approval, failed, and interrupted tasks; task details and project-scoped approvals remain available.

Release note: Task Center now offers Current project or All projects and groups tasks needing attention under Active, while retaining project labels and approval actions.

docs/architecture/automation-platform-architecture.md

@@ -425,9 +425,8 @@ Renderer 只通过显式 IPC 列出、加入、删除、提升、释放和接收
 
 ```text
 任务中心
-├─ 需要关注
 ├─ 进行中
-├─ 已暂停
+├─ 暂停
 └─ 已结束
    └─ 打开任务自身