Single window (900x720, dark background) loading web/index.html with a
Python bridge exposing list_existing_commands, list_exes,
list_sound_names, preview_sound, slugify, validate_draft, save_command,
plus llm_suggest hook for M3. Sound preview spawned on a daemon thread
so the GUI does not block.
Uses ruamel.yaml so existing comments / formatting in commands.yaml
survive a save. Each write creates commands.yaml.bak first, then
atomically renames a .tmp file into place. Tests cover round-trip for
all action types plus comment-preservation on append.