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/routes/post/[slug]/+page.server.ts

@@ -12,7 +12,8 @@ import {
   getPostImageField,
   formatPostDate,
 } from '$lib/blog-utils';
-import { POST_RESOLVE } from '$lib/constants';
+import { POST_RESOLVE, POST_SOCIAL_IMAGE_TRANSFORM, SITE_NAME } from '$lib/constants';
+import { env } from '$env/dynamic/public';
 import { error } from '@sveltejs/kit';
 import { marked } from 'marked';
 
@@ -47,6 +48,21 @@ export const load: PageServerLoad = async ({ params, locals, url }) => {
       })
     : null;
 
+  const siteBaseUrl = (env.PUBLIC_SITE_URL || '').replace(/\/$/, '');
+  const canonical = `${siteBaseUrl}/post/${slug}/`;
+  const postSocialImageRel = postImageField
+    ? await ensureTransformedImage(postImageField.url, {
+        ...POST_SOCIAL_IMAGE_TRANSFORM,
+        focalX: postImageField.focal?.x,
+        focalY: postImageField.focal?.y,
+      })
+    : null;
+  const postSocialImageAbs = postSocialImageRel
+    ? postSocialImageRel.startsWith('/')
+      ? `${siteBaseUrl}${postSocialImageRel}`
+      : postSocialImageRel
+    : null;
+
   const postDate = formatPostDate(post.created);
 
   const postContent = (post as { content?: string }).content;
@@ -63,6 +79,14 @@ export const load: PageServerLoad = async ({ params, locals, url }) => {
     ((post as { row2Content?: unknown[] }).row2Content?.length ?? 0) > 0 ||
     ((post as { row3Content?: unknown[] }).row3Content?.length ?? 0) > 0;
 
+  const siteName =
+    (import.meta.env.PUBLIC_SITE_NAME as string | undefined) || SITE_NAME;
+  const postCreated = (post as { created?: string }).created ?? null;
+  const postUpdated = (post as { updated?: string }).updated ?? postCreated;
+  const postAuthor = (post as { author?: string }).author ?? null;
+  const postHeadline = post.headline ?? post.linkName ?? slug;
+  const postDescription = post.seoDescription ?? post.subheadline ?? post.excerpt ?? '';
+
   const isEvent = !!(post as { isEvent?: boolean }).isEvent;
   const eventDateRaw = (post as { eventDate?: string }).eventDate ?? null;
   const eventDateLabel =
@@ -104,6 +128,68 @@ export const load: PageServerLoad = async ({ params, locals, url }) => {
     .replace(/\{\{PAGE_TITLE\}\}/g, post.headline ?? post.linkName ?? slug);
   const showCommentSection = (post as { showCommentSection?: boolean }).showCommentSection !== false;
 
+  const jsonLd: Record<string, unknown>[] = [];
+  const articleLd: Record<string, unknown> = {
+    '@context': 'https://schema.org',
+    '@type': isEvent ? 'Article' : 'BlogPosting',
+    headline: postHeadline,
+    mainEntityOfPage: { '@type': 'WebPage', '@id': canonical },
+    url: canonical,
+    inLanguage: 'de-DE',
+    ...(postDescription ? { description: postDescription } : {}),
+    ...(postCreated ? { datePublished: postCreated } : {}),
+    ...(postUpdated ? { dateModified: postUpdated } : {}),
+    ...(postSocialImageAbs ? { image: postSocialImageAbs } : {}),
+    author: {
+      '@type': postAuthor ? 'Person' : 'Organization',
+      name: postAuthor ?? siteName,
+    },
+    publisher: {
+      '@type': 'Organization',
+      name: siteName,
+      ...(siteBaseUrl ? { url: siteBaseUrl } : {}),
+    },
+  };
+  jsonLd.push(articleLd);
+
+  if (isEvent && eventDateRaw) {
+    const eventLd: Record<string, unknown> = {
+      '@context': 'https://schema.org',
+      '@type': 'Event',
+      name: postHeadline,
+      startDate: eventDateRaw,
+      eventAttendanceMode: 'https://schema.org/OfflineEventAttendanceMode',
+      eventStatus: 'https://schema.org/EventScheduled',
+      url: canonical,
+      inLanguage: 'de-DE',
+      ...(postDescription ? { description: postDescription } : {}),
+      ...(postSocialImageAbs ? { image: postSocialImageAbs } : {}),
+      organizer: {
+        '@type': 'Organization',
+        name: siteName,
+        ...(siteBaseUrl ? { url: siteBaseUrl } : {}),
+      },
+      ...(eventLocation?.text
+        ? {
+            location: {
+              '@type': 'Place',
+              name: eventLocation.text,
+              ...(hasCoords
+                ? {
+                    geo: {
+                      '@type': 'GeoCoordinates',
+                      latitude: eventLocation.lat,
+                      longitude: eventLocation.lng,
+                    },
+                  }
+                : {}),
+            },
+          }
+        : {}),
+    };
+    jsonLd.push(eventLd);
+  }
+
   return {
     post,
     postImageUrl,
@@ -120,9 +206,11 @@ export const load: PageServerLoad = async ({ params, locals, url }) => {
     mapLinkUrl,
     commentSlot: showCommentSection ? commentSlot : '',
     translations,
-    seoTitle: post.seoTitle ?? post.headline ?? post.linkName ?? slug,
-    seoDescription: post.seoDescription ?? post.subheadline ?? post.excerpt ?? '',
-    socialImage: postImageUrl ?? undefined,
+    seoTitle: post.seoTitle ?? postHeadline,
+    seoDescription: postDescription,
+    socialImage: postSocialImageAbs ?? postImageUrl ?? undefined,
+    robots: (post as { seoMetaRobots?: string }).seoMetaRobots ?? undefined,
+    jsonLd,
     breadcrumbItems: [
       { href: '/', label: 'Start' },
       { href: '/posts/', label: 'Beiträge' },