Apply remaining audit fixes; document radii and code palette in DESIGN.md

- Token sweep: exact-value gold literals now use --wg-border /
  --wg-border-soft / --wg-focus
- Topbar: drop invalid role="menuitem" (no parent role="menu")
- topics_list: topic-select icons get role="checkbox", tabindex,
  aria-label; client.js makes them keyboard-operable and syncs
  aria-checked
- category.tpl: copy-handle link gets an accessible name, "View
  Original" moved to i18n, external-link icon aria-hidden, stretched
  link inside aria-hidden alert removed from tab order
- Footer: all copy moved to [[westgate:footer.*]] keys; year injected
  via filter:middleware.renderFooter instead of hard-coded 2026
- client.js: batch table measurements before writes (no interleaved
  reflow), .catch on the category class map so search results never
  hang, category selector match uses fw-bold class instead of inline
  style
- Forced-colors focus fallback: transparent outline alongside the
  box-shadow focus ring
- DESIGN.md: real radius scale (3/4/6/8px), code-block palette,
  motion & modes section, placeholder alpha

Verified against the sow-nodebb dev container: themed code blocks
render in posts, footer i18n + year, checkbox roles in served HTML.

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

lib/theme.js

@@ -178,6 +178,11 @@ library.filterMiddlewareRenderHeader = async function (hookData) {
 	return hookData;
 };
 
+library.filterMiddlewareRenderFooter = async function (hookData) {
+	hookData.templateData.currentYear = new Date().getFullYear();
+	return hookData;
+};
+
 // generated avatars stay in the court's palette instead of core's material-design brights;
 // core deterministically remaps any stored color not in this list (src/user/data.js)
 library.getIconBackgrounds = async function (data) {