seo: use banner PNG as default OG image, skip SVG logos for social

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

src/lib/constants.ts

@@ -5,7 +5,7 @@
 
 /** Platzhalter-Bild für og:image / twitter:image, wenn weder Page/Post-Bild noch Logo gesetzt ist. */
 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";
+  "/api/assets/windwiderstand_banner.png?_environment=windwiderstand";
 
 /** og:image-Dimensionen (Facebook/Twitter empfehlen 1200×630, 1.91:1). */
 export const SOCIAL_IMAGE_DIMENSIONS = {

src/routes/+layout.server.ts

@@ -311,7 +311,8 @@ export const load: LayoutServerLoad = async ({ locals, route }) => {
   // og-taugliches Social-Image parallel zum Rest — kein sequenzielles Warten.
   let logoSocialImage: string | null = null;
   try {
-    const source = logoUrl ?? DEFAULT_SOCIAL_IMAGE_URL;
+    const isSvgLogo = logoUrl?.split('?')[0].toLowerCase().endsWith('.svg');
+    const source = (logoUrl && !isSvgLogo) ? logoUrl : DEFAULT_SOCIAL_IMAGE_URL;
     const transformed = await ensureTransformedImage(source, SOCIAL_IMAGE_TRANSFORM);
     logoSocialImage = transformed.startsWith('/')
       ? `${siteBaseUrl}${transformed}`