feat(terminal): report Claude Code status; fix stuck Codex sessions

[noih]

Summary

• report Claude Code turn lifecycle in native terminals through UserPromptSubmit / Stop / Notification / SessionEnd hooks injected as inline --settings JSON, leaving the user's own ~/.claude/settings.json untouched
• generalize the Codex-only inject_codex_notify into inject_lifecycle_hook and add a terminal:idle event
• emit a final terminal:idle when a tailer loses its terminal, so quitting either CLI no longer pins the session to "in progress" until the app restarts
• key the signal file by terminal id, so a reopened session terminal cannot have its file unlinked by the outgoing tailer
• treat worker_permission_prompt as attention, so subagent prompts surface like top-level ones
• reclaim orphaned signal files, and skip instrumentation when launch args already carry --settings or -c notify=
• drop the per-terminal PATH shim; it did not instrument hand-launched CLIs in practice

Builds on #634, which added this mechanism for Codex.

Why

Codex's notify only fires agent-turn-complete, so nothing reports the CLI exiting — and clear_attention_on_input reads the Enter that submits /exit as a prompt submit, flipping the session to working right before the CLI dies. Terminal sessions have no run transcript, so that stale flag is the only thing driving their badge; it stayed on "in progress" until the app restarted.

The signal file was keyed by session but deleted by a thread that lives and dies with its terminal, so reopening a session terminal inside the outgoing tailer's 200 ms poll window let the old thread unlink the new terminal's file.

Test plan

• bun run check:all — typecheck, lint, rustfmt, clippy -D warnings, 2116 frontend tests, 1116 Rust tests
• new Rust tests: Claude hook payload and arg ordering, tailer teardown drain and cleanup, worker_permission_prompt
• new frontend tests: terminal:working / attention / idle handlers, sound and notification suppression
• git diff --check

Manual test

1. Submit a prompt in a native Claude Code session; confirm it shows as running, then as waiting on completion (sound, plus a banner when unfocused).
2. Approve a permission prompt, including one raised by a subagent; both surface as attention.
3. Quit with /exit, then with Ctrl-C twice; the session returns to idle instead of staying "in progress". Repeat with Codex.
4. Close a session terminal and immediately reopen it; status still tracks correctly.

Tested on macOS. Windows + WSL is untested and likely still silent: the #[cfg(windows)] hook commands are handed to a Linux hook runner when the terminal routes through wsl.exe. That predates this change and needs its own issue.