Feature: Reactive Query Parameters in Router

[eugenioenko]

Currently, the Router only reacts to changes in the URL path. If the query string changes (e.g., from /search?q=apple to /search?q=orange), components are not notified and do not re-render.

We should expose query parameters as reactive signals so components can respond to filter or search changes without a full route transition.

Tasks:

• Update Router to parse window.location.search into an object.
• Wrap query parameters in a signal.
• Pass the query signal to components via this.args.query.
• Ensure _navigate triggers an update when query params change, even if the path remains the same.