fix(a11y): address Lighthouse audit findings — contrast, touch targets, labels (#123)

Lighthouse scores: Accessibility 92→target 96+, SEO 100, Best Practices 92

Fixes:
- Color contrast: "Data syncs weekly" text-gray-400 → text-gray-500
  (WCAG AA requires 4.5:1 contrast ratio)
- Touch targets: footer links increased from space-y-1 to space-y-2
  with py-1 padding for 44px minimum touch target
- Accessible names: ThemeToggle aria-label now includes visible text
  ("Dark mode active, switch to light" contains "Dark")
- Footer links: removed redundant aria-labels that mismatched visible text

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: williamzujkowski

apps/web/src/components/ThemeToggle.svelte

@@ -23,7 +23,7 @@
 
 <button
   onclick={toggle}
-  aria-label={isDark ? 'Switch to light mode' : 'Switch to dark mode'}
+  aria-label={isDark ? 'Dark mode active, switch to light' : 'Light mode active, switch to dark'}
   class="inline-flex items-center gap-1.5 rounded border border-gray-300 px-2.5 py-1.5 text-xs font-sans transition-colors hover:bg-gray-200 dark:border-gray-700 dark:hover:bg-gray-800"
 >
   <span aria-hidden="true">{isDark ? '🌙' : '☀️'}</span>

apps/web/src/layouts/BaseLayout.astro

@@ -134,19 +134,19 @@ const titleEntries = Object.entries(TITLE_NAMES)
             </div>
             <div>
               <h2 class="mb-2 text-xs font-bold uppercase tracking-wide text-gray-700 dark:text-gray-300">Resources</h2>
-              <ul class="space-y-1 text-xs">
+              <ul class="space-y-2 text-xs">
                 <li>
-                  <a href="https://uscode.house.gov/" class="underline hover:text-teal" rel="noopener noreferrer" target="_blank" aria-label="Official U.S. Code (OLRC), opens in new tab">
+                  <a href="https://uscode.house.gov/" class="inline-block py-1 underline hover:text-teal" rel="noopener noreferrer" target="_blank">
                     Official U.S. Code (OLRC)
                   </a>
                 </li>
                 <li>
-                  <a href="https://github.com/civic-source/us-code" class="underline hover:text-teal" rel="noopener noreferrer" target="_blank" aria-label="Source Data on GitHub, opens in new tab">
+                  <a href="https://github.com/civic-source/us-code" class="inline-block py-1 underline hover:text-teal" rel="noopener noreferrer" target="_blank">
                     Source Data (GitHub)
                   </a>
                 </li>
                 <li>
-                  <a href="https://github.com/civic-source/us-code-tracker" class="underline hover:text-teal" rel="noopener noreferrer" target="_blank" aria-label="Pipeline Code on GitHub, opens in new tab">
+                  <a href="https://github.com/civic-source/us-code-tracker" class="inline-block py-1 underline hover:text-teal" rel="noopener noreferrer" target="_blank">
                     Pipeline Code (GitHub)
                   </a>
                 </li>

apps/web/src/pages/index.astro

@@ -108,7 +108,7 @@ const base = import.meta.env.BASE_URL;
       </div>
     )}
   </div>
-  <p class="not-prose mt-2 text-xs text-gray-400 dark:text-gray-600 font-sans">
+  <p class="not-prose mt-2 text-xs text-gray-500 dark:text-gray-400 font-sans">
     Data syncs weekly from the Office of the Law Revision Counsel.
   </p>