fix(a11y): ta bort alfa-tonad textfärg — 82 kontrastöverträdelser (UI-09)

axe-core 4.10.2 mot 0pt.app 2026-09-26: en enda regel, color-contrast,
impact=serious, 82 noder. Estatets största enskilda a11y-defekt. Alla 82
har samma form: en Tailwind-alfamodifierare på en textfärg.

Uppmätt WCAG 2.2-kontrast mot bägge temabakgrunderna i styles/globals.css:

  text-muted-foreground        4.73:1 ljust   7.63:1 mörkt   GODKÄNT
  text-muted-foreground/70     2.71:1         4.20:1         faller
  text-muted-foreground/60     2.29:1         3.37:1         faller
  text-muted-foreground/50     1.96:1         2.67:1         faller
  text-muted-foreground/40     1.69:1         2.11:1         faller
  text-foreground/20           1.57:1         1.74:1         faller

Den omodifierade token klarar AA i bägge teman, så åtgärden är helt enkelt
att aldrig tona den. Elva textställen bytte till text-muted-foreground.
Kopieringsknappen i app/portal går från 1.57:1 till 4.73:1 i viloläge och
19.79:1 vid hover — den föll även 1.4.11 för icke-textkomponenter.
Toastens stängknapp klarade redan 1.4.11 (3.71:1) men blir 4.73:1.

Kvar med alfa är endast den dekorativa masthead-siffran i app/bestall, som
redan bär aria-hidden + select-none + pointer-events-none. Den är undantagen
både av WCAG och av axe, och guarden nedan tillåter den på just den grunden.

scripts/ci/check-text-contrast.mjs är en blockerande källkodsgrind i
quality-jobbet. Den är avsiktligt inte en axe-körning: den fullständiga
axe-jobb som UI-09 också begär kräver build + serve i CI och spåras separat.
Tills det finns stoppar den här grinden regressionen vid den form som
orsakade defekten.

Refs: UI-09
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

scripts/ci/check-text-contrast.mjs

@@ -0,0 +1,74 @@
+#!/usr/bin/env node
+/**
+ * Blocking guard for finding UI-09 (measured 2026-09-26): 0pt.app carried 82
+ * `color-contrast` violations at axe-core 4.10.2 impact=serious — the estate's
+ * single largest a11y defect. Every one of them came from the same shape: a
+ * Tailwind alpha modifier on a muted text colour.
+ *
+ * Measured WCAG 2.2 contrast against the two theme backgrounds in
+ * styles/globals.css (--background: oklch(1 0 0) light / oklch(0.145 0 0) dark,
+ * --muted-foreground: oklch(0.556 0 0) / oklch(0.708 0 0)):
+ *
+ *   text-muted-foreground        4.73:1 light   7.63:1 dark   PASS (AA needs 4.5)
+ *   text-muted-foreground/70     2.71:1         4.20:1        FAIL
+ *   text-muted-foreground/60     2.29:1         3.37:1        FAIL
+ *   text-muted-foreground/50     1.96:1         2.67:1        FAIL
+ *   text-muted-foreground/40     1.69:1         2.11:1        FAIL
+ *   text-muted-foreground/10     1.13:1         1.13:1        FAIL
+ *
+ * The unmodified token passes in both themes, so the fix is simply never to
+ * fade it. Purely decorative text is exempt — but it has to SAY so: the element
+ * must carry `aria-hidden`, which is also what makes axe skip it. The single
+ * remaining case (app/bestall/page.tsx, the oversized "01" masthead numeral) is
+ * `aria-hidden` + `select-none` + `pointer-events-none` and is allowed by that
+ * rule.
+ *
+ * This is a source-level guard, not a browser run. The full axe-core job that
+ * UI-09 also asks for needs a build + serve in CI and is tracked separately;
+ * until it exists this stops the regression at the shape that caused it.
+ */
+import { readdirSync, readFileSync, statSync } from 'node:fs';
+import { join, relative } from 'node:path';
+
+const ROOT = new URL('../..', import.meta.url).pathname.replace(/\/$/, '');
+const SKIP = new Set(['node_modules', '.next', '.git', 'dist', 'build', 'coverage', '.turbo']);
+const EXT = /\.(tsx|ts|jsx|js|css)$/;
+/** Alpha-modified colour utilities on TEXT. Background/border alphas are fine. */
+const PATTERN = /\btext-(muted-foreground|foreground|primary|secondary|accent-foreground|card-foreground|popover-foreground)\/\d+/g;
+
+function walk(dir, out = []) {
+  for (const name of readdirSync(dir)) {
+    if (SKIP.has(name)) continue;
+    const p = join(dir, name);
+    if (statSync(p).isDirectory()) walk(p, out);
+    else if (EXT.test(name)) out.push(p);
+  }
+  return out;
+}
+
+const violations = [];
+for (const file of walk(ROOT)) {
+  const src = readFileSync(file, 'utf8');
+  const lines = src.split('\n');
+  lines.forEach((line, i) => {
+    for (const m of line.matchAll(PATTERN)) {
+      // Decorative text is exempt when the element declares itself hidden to AT.
+      // The attribute may sit on an earlier line of the same JSX element.
+      const window = lines.slice(Math.max(0, i - 6), i + 1).join('\n');
+      if (/\baria-hidden\b/.test(window)) continue;
+      violations.push({ file: relative(ROOT, file), line: i + 1, token: m[0], text: line.trim() });
+    }
+  });
+}
+
+if (violations.length) {
+  console.error(`\n✗ ${violations.length} alpha-faded text colour(s) found — WCAG 2.2 AA 1.4.3 (finding UI-09).\n`);
+  for (const v of violations) {
+    console.error(`  ${v.file}:${v.line}  ${v.token}`);
+    console.error(`    ${v.text.slice(0, 160)}`);
+  }
+  console.error('\n  Use the unmodified token (text-muted-foreground = 4.73:1 light / 7.63:1 dark).');
+  console.error('  If the text really is decoration, put aria-hidden on the element.\n');
+  process.exit(1);
+}
+console.log('✓ no alpha-faded text colours — WCAG 2.2 AA 1.4.3 contrast shape is clean (UI-09)');