Refactor: Remove query/onQueryChange props, use m.route.param directly for...

Refactor: Remove query/onQueryChange props, use m.route.param directly for search\n\n- Eliminate all query/onQueryChange props and state from page, layout, and list components\n- SearchBar and SongList now read and update the search query directly via m.route.param and m.route.set\n- Simplifies prop passing and makes search state fully URL-driven and idiomatic Mithril.js