A panel drop-down's command rows are full-width rows that take the theme's hover background
(icon, label and shortcut on it) when hovered or focused. Up/Down move the focus through the
enabled rows, Enter starts the command, Escape closes the drop-down. Rows publish
`dropdown:<id>` and the highlighted one `dropdown_hot:<id>`; scenario s46 checks pointer and
keyboard highlight.
Fixes#288
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RjGw4gA5ZvKrU8MQP6sBgT