Catppuccin, Gruvbox, Solarized and High contrast themes

Each in light and dark. The published palettes missed AA in 19 places,
mostly Solarized and Catppuccin Latte, so each failing colour is moved
the least distance, toward black or white, that clears every pair it is
drawn in. Solarized dark's base0 had to rise to base1 to read on base02,
so its dim sits between base2 and base1 to keep three steps of type.

tests/contrast.js checks every palette against the pairs the page draws,
and a border that matches the ground it sits on. Its first run caught
Classic's links at 3.7:1 on the source list and Modern's faint at 4.3:1
on inputs; both are tuned. A failed toast moves to --panel, since the
error colours are tuned for the page's grounds, not --raise.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

CLAUDE.md

@@ -100,6 +100,7 @@ Patching that file by guessing an anchor string has failed repeatedly. Read the
 cargo test                # ~80 tests: parsing, filters, retention, schedules, SQL, per-user state
 npx tsc -p .              # type-checks web/src
 node tests/page-smoke.js
+node tests/contrast.js    # every theme's palette against WCAG AA
 npx playwright test       # 40 browser tests against a real daemon on fixture feeds
 ```