fix(web): text on a tint of its own hue uses the house -fg tokens (#3150)

A hue painted as text on a color-mix tint of itself sits close to the
surface under it. On Minstrel's surfaces the raw accent on its 15% tint
measures 1.97:1 at worst (dark mode, hover surface), against AA's 4.5.

- tokens.json gains colors.fg: the five FabledSword -fg formulas (accent
  45%, success 45%, warning, error and info 50%), each mixed toward
  parchment so one declaration serves both modes. Success is Minstrel's
  moss. tokens-to-css emits them in :root.
- Tailwind exposes them as text-accent-fg, text-warning-fg, text-error-fg
  and text-info-fg.
- 23 sites swapped: 14 Tailwind class strings (PlayerBar and the admin
  count pills) and 9 CSS rules (StatusPill's four tones and five accent
  chips). Worst case after: accent-fg 5.03, error-fg 4.75, warning-fg
  4.92, success-fg 4.85.
- scripts/check-tint-contrast.js finds the pair in either spelling. Its
  test scans src in the web Vitest lane and fails on any new site, with
  fixture cases showing it can fail.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/tailwind.config.js

@@ -25,11 +25,14 @@ export default {
         },
         accent: {
           DEFAULT: 'var(--fs-accent)',
-          tint: 'color-mix(in srgb, var(--fs-accent) 12%, transparent)'
+          tint: 'color-mix(in srgb, var(--fs-accent) 12%, transparent)',
+          // Accent TEXT on an accent tint (#3150). The raw accent on its own
+          // tint measures 1.97:1 at worst; this measures 5.03.
+          fg: 'var(--fs-accent-fg)'
         },
-        warning: 'var(--fs-warning)',
-        error: 'var(--fs-error)',
-        info: 'var(--fs-info)'
+        warning: { DEFAULT: 'var(--fs-warning)', fg: 'var(--fs-warning-fg)' },
+        error: { DEFAULT: 'var(--fs-error)', fg: 'var(--fs-error-fg)' },
+        info: { DEFAULT: 'var(--fs-info)', fg: 'var(--fs-info-fg)' }
       },
       borderRadius: {
         sm: 'var(--fs-radius-sm)',