Beast/ux overhaul

[dewabisma]

New design overhaul.

Note

Low Risk
Mostly styling, Storybook, and dev tooling; no auth or data-path changes in the shown diff.

Overview
Locks the explorer to a dark-only presentation at the document root: index.html sets class="dark", updates theme-color to #0E0E0E, switches the apple touch icon, and makes #app a full-height flex column. Storybook matches the app by removing the light/dark toolbar, defaulting backgrounds to dark, and always applying dark on html/body.

Typography and dependencies swap Inter/JetBrains Mono for Geist Sans/Mono (@fontsource/geist-*), and drop unused Radix separator/switch plus the @svgr/cli pipeline (gen-assets script removed from package.json).

Adds Cursor rules for Bun as the package runner and for using the shared page-title / page-subtitle classes on route headings. .gitignore now ignores /new-ux.

^{Reviewed by Cursor Bugbot for commit 1a22df9. Configure here.}