Navigation inspector UI updates (#94959)
Updates the Navigation Inspector panel UI to match the new
shell-inspection design.
- Reworks the idle, waiting, static shell, and client shell states
around the new “Pause on navigations” toggle
- Adds full-width waiting/debugger banners, updated copy, URL labels,
and the `Resume` action
- Simplifies the panel expansion animation so only the panel
opens/closes, without fading the inner content
To try it out, run
```
pnpm next dev test/development/app-dir/instant-navs-devtools
```
https://github.com/user-attachments/assets/271d788e-87b9-4787-8d31-8008b9e693c0
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Co-authored-by: vercel[bot] <35613825+vercel[bot]@users.noreply.github.com>
