The footer chips already advertised ↑↓ to navigate and ↵ to open;
they now match reality.
- chrome::command_match exposes COMMAND_ACTIONS / matching_actions
alongside the tab/history/bookmark match helpers and a
CommandSelection enum + visible_command_rows that returns the flat
ordered list of activatable rows. command_overlay drops its private
copies of the action const and matcher and consumes them from the
shared module so render and key handling share one source of truth.
- ElyShell tracks command_selected_index with command_select_next /
command_select_prev (cyclic, no notify when index doesn't change)
and activate_selected_command which dispatches the right shell call
for the currently selected CommandSelection variant and dismisses
the overlay. Dismissing command mode resets the index to 0.
- The shell root captures key_down via on_command_overlay_key_down.
When the live snapshot's command_query starts with '>', up / down
/ enter run the matching helper and the event stops propagating so
the omnibar input doesn't move its caret.
- Each rendered row receives a `selected` flag. The selected row gets
the design's tinted bg + accent-bar on the left edge so the active
result is unambiguous at any keyboard step.