Initial SvelteKit frontend port of windwiderstand.de

Full parity with Astro site: content rows, post/tag routes, pagination,
event badges + OSM map, comments, Live-Search via /api/search-index,
CMS image proxy, RSS, sitemap.

Deploy: Dockerfile + docker-compose.prod.yml + Gitea Actions workflow
to build + push to git.pm86.de registry and ssh-deploy to Contabo.

src/app.d.ts

@@ -0,0 +1,8 @@
+declare global {
+  namespace App {
+    interface Locals {
+      translations: Record<string, string>;
+    }
+  }
+}
+export {};