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/constants.ts

@@ -7,10 +7,22 @@
 export const DEFAULT_SOCIAL_IMAGE_URL =
   "https://images.ctfassets.net/xjxq6v7l1pfe/43yZHpF9OCnrBlEWHJSZMK/1ef20b265ea1e4e55317812ee5ae6b4c/simple-green-tree-illustrated-watercolor-with-gentle-shading-great-rural-scenery-farm-backdrops-naturethemed-designs-landsca.jpg";
 
-/** Parameter für og:image / twitter:image (über /cms-images + Disk-Cache). */
+/** og:image-Dimensionen (Facebook/Twitter empfehlen 1200×630, 1.91:1). */
+export const SOCIAL_IMAGE_DIMENSIONS = {
+  width: 1200,
+  height: 630,
+} as const;
+
+/** Logo-Fallback für og:image: letterboxed (contain), damit Logo komplett sichtbar bleibt. */
 export const SOCIAL_IMAGE_TRANSFORM = {
-  width: 200,
-  height: 200,
+  ...SOCIAL_IMAGE_DIMENSIONS,
+  fit: "contain" as const,
+  format: "webp" as const,
+};
+
+/** Post-Bild für og:image: cover (Banner-Look), Focal wird separat übergeben. */
+export const POST_SOCIAL_IMAGE_TRANSFORM = {
+  ...SOCIAL_IMAGE_DIMENSIONS,
   fit: "cover" as const,
   format: "webp" as const,
 };