While a turn is in flight (`is_loading`), the model/permission surface the
engine is acting on must not shift underneath it. User-initiated mode cycling
(cycle_mode / cycle_mode_reverse) and thinking cycling (cycle_effort) are now
refused with a concise status message ("… is locked while a turn is running —
press Esc to interrupt first") and the selection stays put (the chip "twitches"
back rather than moving). Internal set_mode transitions (YOLO/plan) are
unaffected — only the user gestures are guarded.
Unit-tested: locked while is_loading, works again once idle. Persistent
busy/free chip styling is left for a visual-review pass.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Hunter B
04aa64d569