Removes the light/dark toggle infrastructure in favor of a single dark
theme. Deletes the theme context, boot script, light-mode CSS overrides,
logotype-light asset, and the pierre-light diff theme. Collapses
graph-theme into a single constant. Adds scheme-only-dark on <html> so
native controls and the server-injected Graphviz @media query render
dark.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Remove the system color-scheme fallback from the web UI theme boot path.
Fabro now uses a saved light/dark preference when present and otherwise
starts in dark mode by default. Add a regression test for the shared
theme selection helper and refresh the built web assets.
Replace the old React Router SSR setup with a static SPA build served by
fabro-server, move setup and GitHub auth handling into Rust, and update the
default local web URL and stale Arc-era references to match the Fabro name.
