Each key field (Start/Stop+paste/Stop+paste+Enter/Cancel, and the preset
Hotkey) gets a Set button that captures the next keypress and writes it in the
config format. Captures modifier-only chords (e.g. Ctrl+Win -> <ctrl>+<cmd>) by
accumulating pressed keys and finalising on first release; key events are
swallowed while binding so they don't leak into the UI. Tested: token mapping,
combo formatting, and the bind flow.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>