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>

web/login.html

@@ -17,7 +17,7 @@
   --line:#2c3849;
   --fg:#f5f5f5;      /* #F5F5F5 device highlight */
   --dim:#95a0b1;     /* #95A0B1 straight from the icon's blue-grey */
-  --faint:#7a8799;  /* lifted from the icon ramp until it clears AA at small sizes */
+  --faint:#7e8b9c;  /* lifted from the icon ramp until it clears AA at small sizes */
   --accent:#92b2e6;  /* #92B2E6 the screen blue */
   --accent2:#f49e2c; /* #F49E2C the EQ bars */
   --ink:#0e131b;     /* text on an accent fill */