The top bar is getting quite wide with all of its button toggle groups.
This:
- Converts the Compressed/Uncompressed and Client/Server toggles to
shadcn `<Select>`s
- Adds a custom `<MultiSelect>` implementation since this is missing in
shadcn. This composes shadcn’s popovers and a series of checkboxes,
along with accessibility attributes and keyboard shortcuts.
- Uses this `<MultiSelect>` for the type filter
- Removes the divider between these since there aren’t any groups left
to divide
<img width="1547" height="719" alt="image"
src="https://github.com/user-attachments/assets/4041f6b7-2a47-4e17-b020-448ac0103740"
/>
- Adds decorated kbd-style shortcut labels to cue the user into using them
- Listens only for the appropriate OS or Ctrl key on Mac/Others
- Esc now clears and focuses the search field and the treemap focus
- Does not trigger in the case where the user has another element focused

This adds an interactive Treemap-style bundle analyzer app to the Next.js codebase and writes a copy to disk when `next build --experimental-analyze` is run.
* It's a separate app in `apps/bundle-analyzer` as `@next/bundle-analyzer-ui` that uses `output: 'export'` to export a purely static Next.js app
* These static resources are copied into Next.js's published `dist` directory in the `next` package itself. Users never depend on `@next/bundle-analyzer-ui`
* When users run `next build --experimental-analyze`, these static resources are copied into the user's `.next/diagnostics/analyze` along with the data payloads needed to visualize the user's app
In an upcoming PR, we'll add `next experimental-analyze` that will create analysis files without build artifacts, as well as optionally start a static file server.
Test Plan: Ran `next build --experimental-analyze` in a test app and ran a static file server to run it.