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/lib/ui/Radio.svelte

@@ -0,0 +1,25 @@
+<script lang="ts">
+  /** Gleicher name für alle Radios in einer Gruppe; bind:group vom Parent hält den gewählten value. */
+  let {
+    name = '',
+    value = '',
+    /** Gebundener Wert der Gruppe – entspricht dem value des ausgewählten Radios. */
+    group = $bindable(''),
+    disabled = false,
+    label = '',
+  } = $props();
+</script>
+
+<label class="inline-flex cursor-pointer items-center {disabled ? 'cursor-not-allowed opacity-60' : ''}">
+  <input
+    type="radio"
+    {name}
+    {value}
+    bind:group={group}
+    {disabled}
+    class="h-5 w-5 rounded-full border-[1.5px] border-stein-400 text-wald-500 hover:border-wald-400 focus:ring-2 focus:ring-wald-100 focus:ring-offset-0 checked:border-wald-500 checked:bg-wald-500"
+  />
+  {#if label}
+    <span class="ml-2 text-base text-stein-700">{label}</span>
+  {/if}
+</label>