test: vitest unit + playwright e2e suites; fix a11y, contrast, no-JS reveal

- vitest: dictionary parity, slug-map bijection, content-schema validation, JSON-LD (23)
- playwright: both locales, language-switch mapping (incl. no-JS), CV downloads,
  form happy-path + honeypot, axe a11y on 5 templates x 2 themes (23)
- fix: raise ink-faint + light accent to meet WCAG AA 4.5:1 (axe-verified)
- fix: gate reveal animations behind html.js so content is visible without JS
  (progressive enhancement - was hidden at opacity 0); scan reduced-motion path
- fix: validate contact form before the anti-bot time-trap (no false success)
- chore: ESLint node globals, typed diagram props, resvg fontFiles, prettier pass

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

site/src/components/core/ThemeScript.astro

@@ -8,13 +8,16 @@
 
 <script is:inline>
   (function () {
+    // Mark that JS is available; reveal animations are gated behind html.js so
+    // content stays visible without JavaScript.
+    document.documentElement.classList.add('js');
     try {
-      var t = localStorage.getItem('theme');
+      let t = localStorage.getItem('theme');
       if (t !== 'light' && t !== 'dark') {
         t = window.matchMedia('(prefers-color-scheme: light)').matches ? 'light' : 'dark';
       }
       document.documentElement.dataset.theme = t;
-    } catch (e) {
+    } catch {
       document.documentElement.dataset.theme = 'dark';
     }
   })();