feat(page): inline topImage field, fallback to topFullwidthBanner

Reads page.topImage first (new direct image field on the page schema);
falls back to legacy topFullwidthBanner.image during transition. Same
ResponsiveImage build, social-image transform and warm-up as before.
Banner-object still passed through so existing rendering keeps working
when headline/subheadline/variant are wanted; pure-image migration
needs no further code changes.

Schema + 21 pages migrated CMS-side in the same change set.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

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

@@ -67,22 +67,26 @@ export const load: PageServerLoad = async ({ params, locals, fetch, url, setHead
   ]);
   sanitizeBlocks(page);
 
-  // Resolve top banner if present
+  // Top-Bild: bevorzugt neues inline-Feld `topImage`, sonst Legacy via
+  // topFullwidthBanner-Referenz. Banner-Bild ist auch Social-Image-Quelle.
   let topBannerResolvedImages: string[] = [];
   let topBannerResponsive: ResponsiveImage | null = null;
   let topBannerFocalCss: string | null = null;
-  // Banner-Bild ist auch unsere Social-Image-Quelle (1200×630 cover, mit Focal).
   let pageSocialImageAbs: string | null = null;
-  const bannerRaw = (page as { topFullwidthBanner?: unknown }).topFullwidthBanner;
   const siteBaseUrl = (env.PUBLIC_SITE_URL || '').replace(/\/$/, '');
-  if (bannerRaw && typeof bannerRaw === 'object' && 'image' in bannerRaw) {
-    const bannerImages = Array.isArray((bannerRaw as { image?: unknown }).image)
-      ? ((bannerRaw as { image?: unknown[] }).image ?? [])
-      : (bannerRaw as { image?: unknown }).image != null
-        ? [(bannerRaw as { image?: unknown }).image]
-        : [];
-    if (bannerImages.length > 0) {
-      const primary = extractCmsImageField(bannerImages[0]);
+
+  const topImageRaw = (page as { topImage?: unknown }).topImage;
+  const bannerRaw = (page as { topFullwidthBanner?: unknown }).topFullwidthBanner;
+  const topImageSource: unknown =
+    topImageRaw ??
+    (bannerRaw && typeof bannerRaw === 'object' && 'image' in bannerRaw
+      ? (bannerRaw as { image?: unknown }).image
+      : undefined);
+
+  if (topImageSource) {
+    const imageArr = Array.isArray(topImageSource) ? topImageSource : [topImageSource];
+    if (imageArr.length > 0) {
+      const primary = extractCmsImageField(imageArr[0]);
       if (primary?.url) {
         topBannerFocalCss = focalToCss(primary.focal);
         topBannerResponsive = await buildResponsiveImage(primary.url, {
@@ -101,7 +105,7 @@ export const load: PageServerLoad = async ({ params, locals, fetch, url, setHead
           ? `${siteBaseUrl}${socialRel}`
           : socialRel;
       }
-      topBannerResolvedImages = await resolveImageUrls(bannerImages as string[], {
+      topBannerResolvedImages = await resolveImageUrls(imageArr as string[], {
         width: 2000,
         height: 750,
         fit: 'cover',
@@ -125,9 +129,11 @@ export const load: PageServerLoad = async ({ params, locals, fetch, url, setHead
       { href: '/', label: 'Start' },
       { label: page.headline ?? page.linkName ?? page.slug ?? page._slug ?? slug },
     ],
-    topBanner: bannerRaw
+    topBanner: topImageSource
       ? {
-          banner: bannerRaw as import('$lib/cms').FullwidthBannerEntry | null,
+          banner:
+            (bannerRaw as import('$lib/cms').FullwidthBannerEntry | null) ??
+            null,
           resolvedImages: topBannerResolvedImages,
           responsive: topBannerResponsive,
           focalCss: topBannerFocalCss,