feat(tui): ring a turn-done notification when the terminal is unfocused

[Max17190]

Why

A turn finishing while the user is in another window ends silently; the bell fires only when an approval arrives, so long turns mean polling the terminal.

Summary

Track terminal focus from focus-change reports (term_focus: Option<bool>, None until the terminal sends one). On the working-to-idle presence edge while known unfocused, emit an OSC 9 notification plus a bell. Terminals that never report focus stay silent rather than ringing at a watching user; the needs-approval bell keeps its unconditional ring. EnableFocusChange is symmetric with the other terminal modes on init and every exit path.

Test Plan

• turn_done_ring_fires_only_on_the_unfocused_working_to_idle_edge: full truth table for the ring decision (shown red with the decision neutered).
• focus_reports_track_terminal_focus: focus events update the tracked state (shown red with tracking neutered).
• cargo test --workspace and cargo clippy --workspace --all-targets clean.

Greptile Summary

This change tracks terminal focus and rings when an unfocused turn becomes idle. The normal shutdown path disables focus reporting, but the panic cleanup path does not, so a crash can leave the shell receiving terminal focus escape sequences after OpenMax exits. The TUI binary test suite passed with 246 tests.

Confidence Score: 4/5

Not merge-safe until panic cleanup disables terminal focus reporting.

There is one independent P1 finding, and it is not a security issue; the required scoring table assigns a score of 4.

Files Needing Attention: crates/tui/src/main.rs: add focus-reporting cleanup to the panic path.

T-Rex Logs

What T-Rex did

• T-Rex produced a proof for a posted P1 finding and linked it to the review comment for details.
• T-Rex created a Rust harness to exercise focus-reporting panic cleanup.
• Generated logs showing panic cleanup behavior without panic-hook focus disable for review.
• Generated logs showing panic cleanup behavior with panic-hook focus disable for review.

_{Ran code and verified through T-Rex}

Comments Outside Diff (1)

1. crates/tui/src/main.rs, line 1115-1116 (link)

   Panic cleanup leaves focus reporting enabled

   Focus reporting is enabled before app::run, but it is disabled only after app::run returns normally. A panic runs this hook and unwinds past the normal cleanup at line 1081; the hook restores Ratatui and the title without emitting DisableFocusChange. A compatible terminal therefore continues sending focus escape sequences to the restored shell after an OpenMax panic. Disable focus reporting in this panic cleanup path as well, or use an unwind-safe cleanup guard.

   Artifacts

   
   

   Rust harness for focus-reporting panic cleanup

   • Authored and executed a direct Rust reproduction that emits crossterm focus control sequences around an injected app-boundary panic, showing the normal cleanup is bypassed on unwind.

   Panic cleanup output without panic-hook focus disable

   • Captured command, working directory, exit code, and output for the production-equivalent panic path; it shows focus enable present and focus disable absent.

   Panic cleanup output with panic-hook focus disable

   • Captured command, working directory, exit code, and output for the comparison path with panic-hook focus cleanup; it shows both focus enable and disable sequences.

   

   _{Ran code and verified through T-Rex}

   Prompt To Fix With AI

   This is a comment left during a code review.
   Path: crates/tui/src/main.rs
   Line: 1115-1116
   
   Comment:
   **Panic cleanup leaves focus reporting enabled**
   
   Focus reporting is enabled before `app::run`, but it is disabled only after `app::run` returns normally. A panic runs this hook and unwinds past the normal cleanup at line 1081; the hook restores Ratatui and the title without emitting `DisableFocusChange`. A compatible terminal therefore continues sending focus escape sequences to the restored shell after an OpenMax panic. Disable focus reporting in this panic cleanup path as well, or use an unwind-safe cleanup guard.
   
   ---
   
   For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

Prompt To Fix All With AI

### Issue 1
crates/tui/src/main.rs:1115-1116
**Panic cleanup leaves focus reporting enabled**

Focus reporting is enabled before `app::run`, but it is disabled only after `app::run` returns normally. A panic runs this hook and unwinds past the normal cleanup at line 1081; the hook restores Ratatui and the title without emitting `DisableFocusChange`. A compatible terminal therefore continues sending focus escape sequences to the restored shell after an OpenMax panic. Disable focus reporting in this panic cleanup path as well, or use an unwind-safe cleanup guard.

---

For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

_{Reviews (1): Last reviewed commit: "feat(tui): ring a turn-done notification..." | Re-trigger Greptile}