[FEATURE] Let an agent dispatch a visible Agent View / FleetView session without the manual approve-to-start

Summary

An in-conversation agent has no way to create a visible sidebar (Agent View / FleetView) session that starts automatically. The agent-callable session primitives each fail one half of "visible + unattended":

| Mechanism | Visible in sidebar | Auto-starts (no manual approval) |
|---|---|---|
| spawn_task chip | ✅ yes | ❌ no — always requires the user to approve/click to start |
| Agent / Task subagent | ❌ no (not listed as a sidebar session) | ✅ yes |
| claude --bg | ❌ no (CLI daemon only; doesn't appear in the desktop sidebar) | ✅ yes |

So an agent can produce either a visible session or an unattended one — never both.

Use case

Multi-session orchestration where the user wants to watch worker/review sessions live in the sidebar (see progress, attach if needed) without manually approving/clicking each one. Today, going hands-off forces invisible subagents (can't watch them); staying visible forces a manual approve-to-start per session (can't step away). This is a hard wall when an agent orchestrates a fan-out of fix + review sessions and the user wants it both observable and unattended.

Request

Allow an agent to dispatch a visible sidebar session (in its own worktree) that starts without the manual approve-to-start step — ideally gated behind an explicit opt-in (e.g. a permissions allow-rule or a defaultMode-style toggle), so it stays safe-by-default but users who want unattended-but-observable orchestration can enable it.

Related

• #60437 — Agent View doesn't enumerate FleetView-dispatched / daemon sessions (the CLI vs desktop split that makes claude --bg invisible in the sidebar)
• #60975 — allow specifying cwd when spawning a new agent
• #61134 — group sessions by working directory
• #62154 — archive_session forces per-session prompts / is disabled under bypassPermissions

_Reported while orchestrating multi-session fix/review work via the desktop app._