Fragment mode (for editing studio component/overlays) should navigate with a URL update so that it reloads on persists on reload

Currently, if I reload this page, it takes me back to the main page canvas. I want to stay in the fragment edit mode so persist it in the URL. URL structure should be clean.

Also consider more than 1 level of nesting

Start by tracing how fragment edit mode navigates and how the studio currently represents the active component in the URL. Define a clean URL structure that supports nested fragments, then verify that reloading at each nesting level restores the same edit mode.

Written by the indexing model from the issue text.