feat: update site URLs and enhance image handling

- Changed site URLs in docker-compose and deployment configurations to remove "www" prefix for consistency.
- Improved image handling by introducing warmPostCardImages function for pre-fetching images in posts and tags.
- Enhanced PostCard component with responsive image sizes for better performance.
- Updated layout to include robots meta tag and JSON-LD structured data for improved SEO.
- Added loading state for images in TopBanner component to enhance user experience.

src/lib/rusty-image.server.ts

@@ -255,3 +255,35 @@ export function warmResponsiveImage(
     void fetchFn(u).catch(() => {});
   }
 }
+
+/**
+ * Fire-and-forget Warmup für PostCard-Bilder (Grid: 400px base, 2x density, webp+jpeg).
+ * Spiegelt die URLs, die <RustyImage width={400} aspect="3/2"/> zur Laufzeit anfragt.
+ */
+export function warmPostCardImages(
+  posts: Array<{ _rawImageUrl?: string; _imageFocal?: { x: number; y: number } | null }>,
+  fetchFn: typeof fetch,
+  limit = 6,
+): void {
+  const widths = [400, 800];
+  const formats: Array<'webp' | 'jpeg'> = ['webp', 'jpeg'];
+  for (const post of posts.slice(0, limit)) {
+    const raw = post._rawImageUrl;
+    if (!raw) continue;
+    const focal = post._imageFocal ?? undefined;
+    for (const w of widths) {
+      for (const format of formats) {
+        const url = getCmsImageUrl(raw, {
+          width: w,
+          height: Math.round((w / 3) * 2),
+          fit: 'cover',
+          format,
+          quality: 75,
+          ar: '3/2',
+          ...(focal ? { focalX: focal.x, focalY: focal.y } : {}),
+        });
+        void fetchFn(url).catch(() => {});
+      }
+    }
+  }
+}