v0.2.0: WCAG 2.2 AAA accessibility + toggle fix + version bump

- Upgrade accessibility from WCAG 2.1 AA to WCAG 2.2 AAA conformance
- 42 accessibility fixes across 18 frontend components
- Enhanced contrast ratios (7:1 body text, 4.5:1 large text, 3:1 non-text)
- 44px minimum touch/click targets on all interactive elements
- Full WAI-ARIA 1.2: tablist, radiogroup, alertdialog, progressbar, switch
- Screen-reader-only data tables behind chart, dynamic page titles
- Skip navigation link, semantic heading hierarchy (h1 > h2)
- Celebration popups persist on hover/focus with keyboard dismiss
- Fix ToggleSwitch visual height (44px hit area, 28px visual track)
- Update README with detailed WCAG 2.2 AAA accessibility section
- Include WCAG design doc and implementation plan in docs/plans/

src/lib/components/ToggleSwitch.svelte

@@ -15,19 +15,24 @@
   }
 </script>
 
+<!-- 44px hit area wrapper (WCAG 2.5.8) with compact visual toggle inside -->
 <button
   type="button"
   role="switch"
   aria-label={label}
   aria-checked={checked}
-  class="relative inline-flex h-[28px] w-[52px] min-h-[44px] shrink-0 cursor-pointer rounded-full
-         transition-colors duration-200 ease-in-out"
-  style="background: {checked ? $config.accent_color : '#1a1a1a'};"
+  class="relative inline-flex min-h-[44px] min-w-[52px] shrink-0 cursor-pointer items-center justify-center
+         bg-transparent border-none p-0"
   onclick={toggle}
 >
   <span
-    class="pointer-events-none inline-block h-[22px] w-[22px] rounded-full
-           shadow-sm transition-transform duration-200 ease-in-out
-           {checked ? 'translate-x-[27px] bg-white' : 'translate-x-[3px] bg-[#666]'} mt-[3px]"
-  ></span>
+    class="inline-flex h-[28px] w-[52px] items-center rounded-full transition-colors duration-200 ease-in-out"
+    style="background: {checked ? $config.accent_color : '#1a1a1a'};"
+  >
+    <span
+      class="pointer-events-none inline-block h-[22px] w-[22px] rounded-full
+             shadow-sm transition-transform duration-200 ease-in-out
+             {checked ? 'translate-x-[27px] bg-white' : 'translate-x-[3px] bg-[#666]'}"
+    ></span>
+  </span>
 </button>