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.

docker-compose.yml

@@ -0,0 +1,17 @@
+services:
+  windwiderstand:
+    build: .
+    ports:
+      - "3001:3001"
+    environment:
+      - PUBLIC_CMS_URL=${PUBLIC_CMS_URL:-http://rustycms:3000}
+      - PUBLIC_SITE_URL=${PUBLIC_SITE_URL:-https://www.windwiderstand.de}
+      - PUBLIC_SITE_NAME=${PUBLIC_SITE_NAME:-Windwiderstand}
+      - ORIGIN=${ORIGIN:-https://www.windwiderstand.de}
+      - IMAGE_CACHE_DIR=${IMAGE_CACHE_DIR:-/app/.cache/images}
+    volumes:
+      - image-cache:/app/.cache/images
+    restart: unless-stopped
+
+volumes:
+  image-cache: