The mini timer window was blank because hash-based routing
(createWebHashHistory) doesn't work with Tauri's WebviewUrl path.
Now App.vue detects the mini timer by checking getCurrentWindow().label
=== 'mini-timer' and renders the MiniTimer component directly,
bypassing the router entirely.
The app uses createWebHashHistory but the mini timer window was
opened with WebviewUrl::App("/mini-timer") which sets the URL path,
not the hash fragment. Vue Router never matched the route, so the
Dashboard rendered in a 300x64 window (appearing blank). Now loads
root URL and sets window.location.hash via eval. Also shows/focuses
the main window when closing the mini timer.
