Fixes#28104.
## Summary
Active `/goal` turns should leave the persisted goal paused whenever the
TUI interrupts the running turn. The bug in #28104 showed this most
visibly through `Esc`: some interrupt paths aborted the turn without
updating the goal status, so the goal could remain active and continue
automatically.
This change makes `ChatWidget` pause an active goal before the TUI sends
an interrupt from the status-row path, the pending-steer path, `Ctrl+C`,
or a request-user-input overlay. The modal overlay now reports whether a
key will interrupt the turn, which keeps modal `Esc` and `Ctrl+C`
behavior aligned with the normal interrupt paths.
## Manual Testing
Built the local CLI with `just codex --help`, then launched the local
TUI with goals enabled. Started an active `/goal` turn and interrupted
it with `Esc`, then resumed and repeated with `Ctrl+C`; both paths
showed `Goal paused`, the interrupted-conversation message, and the
`Goal paused (/goal resume)` footer. I also stopped the background
terminal and exited the TUI cleanly after the run.
I did not find a reliable standalone manual path to force the
request-user-input overlay case, so that path is covered by the focused
automated test.
Eric Traut
07298a948c