fix: inherit extra roots on new chats; stop Import resurrecting deleted sessions

[RongleCat]

Fixes #1233
Fixes #1236

Why

Open issues this round: 2 bugs, 3 features. Features stay parked.

#1233 extra-root write still failed on 0.2.36. The bound session used app_ws_*; a new chat in the same project had no workspaceId, so spawn fell back to built-in workspace and Seatbelt blocked the extra folder.

#1236 archive does not resurrect (the App row still links agentSessionId). Delete only dropped the App journal, so the next bulk Import created a new sidebar row for the leftover CLI directory.

What

• New chats (and connect of still-unbound rows) inherit the project's workspace; forks copy the source binding.
• Delete stops live/background/parked ACP, removes the CLI session tree, and tombstones the agent id so import_all cannot recreate the row.
• Bulk import also skips CLI … stubs and System32 / workspaces/general cwd noise.

Out of scope

• [Feature]:一个项目支持配置多个目录 #1232 project-level default multi-root UI
• [Feature]: 【大屏特性】拖拽拆分对话框的功能 #1234 split panes
• [Feature]: 【大屏特性】对话区域两边空白位置 #1235 chat column width
• Archive still hides App-only; CLI grok sessions list unchanged

Tests

• bind_default_workspace_if_unbound_inherits_project_workspace
• fork_session_copies_workspace_binding
• import_all_does_not_resurrect_deleted_app_session
• import_all_skips_tombstoned_id_even_if_cli_dir_remains
• archived_row_is_already_linked_so_import_all_skips
• skip_bulk_import_drops_stubs_and_noise_cwds