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>

scss/westgate/_posts.scss

@@ -245,7 +245,7 @@ li[component="post"] [component="post/reply-count"] {
 li[component="post"] [component="post/actions"] .btn:hover,
 li[component="post"] [component="post/reply-count"]:hover {
 	color: var(--wg-text) !important;
-	background: rgba(194, 163, 90, 0.08) !important;
+	background: var(--wg-border-soft) !important;
 	border-color: rgba(194, 163, 90, 0.2) !important;
 }
 
@@ -334,7 +334,7 @@ li[component="post"] [component="post/downvote"] {
 
 .pagination-block {
 	background:
-		linear-gradient(to bottom, transparent calc(100% - 1px), rgba(194, 163, 90, 0.08) calc(100% - 1px)),
+		linear-gradient(to bottom, transparent calc(100% - 1px), var(--wg-border-soft) calc(100% - 1px)),
 		rgba(18, 15, 22, 0.96) !important;
 	background-size: 100% var(--wg-ledger-line), auto;
 	border-color: var(--wg-ledger-border) !important;