Replace the conditional Select/Input pattern with a unified Combobox
(Input + Command dropdown) that always allows free-text input while
offering autocomplete suggestions from previously tracked events.
Applied to both workflow creation dialog and edit page (trigger event,
add WAIT_FOR_EVENT step, edit WAIT_FOR_EVENT step).
Co-Authored-By: Claude Opus 4.6 (1M context) <[email protected]>
