Theme post code blocks + a11y fixes (impeccable audit) (#25)

Code blocks in posts rendered with the markdown plugin's default light highlight.js theme — white blocks on the dark ledger. This adds dark velvet pre/code styling and a Westgate-toned syntax palette (gold keywords, ledger-ink titles, muted green strings) for post content and the composer preview.

Also picks up the quick wins from an impeccable audit:

- Visible focus ring on the mobile drawer search (input had `outline: 0` with no replacement)
- Input placeholder contrast raised to pass WCAG 4.5:1; tagsinput placeholder reuses the token instead of `$gray-500`
- `prefers-reduced-motion` block zeroing transitions/animations (there were none before)
- Fixed a stray `</li>` closing a `<div>` in `quick-search-results.tpl`

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Reviewed-on: #25
Co-authored-by: vickydotbat <vickydotbat@tutamail.com>
Co-committed-by: vickydotbat <vickydotbat@tutamail.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) {