fix: resolve pipeline timeouts, 418 hydration errors, and english category link 404s

app/[locale]/products/[...slug]/page.tsx

@@ -125,11 +125,26 @@ export default async function ProductPage({ params }: ProductPageProps) {
       ? t(`categories.${categoryKey}.title`)
       : fileSlug;
 
-    const filteredProducts = allProducts.filter((p) =>
-      p.frontmatter.categories.some(
-        (cat) => cat.toLowerCase().replace(/\s+/g, '-') === fileSlug || cat === categoryTitle,
-      ),
-    );
+    const filteredProducts = allProducts.filter((p) => {
+      const firstCat = p.frontmatter.categories[0] || '';
+      const normalizedCat = firstCat.toLowerCase().replace(/\s+/g, '-');
+      let pFileSlug = 'low-voltage-cables';
+      if (normalizedCat === 'hochspannungskabel' || normalizedCat === 'high-voltage-cables')
+        pFileSlug = 'high-voltage-cables';
+      else if (
+        normalizedCat === 'mittelspannungskabel' ||
+        normalizedCat === 'medium-voltage-cables'
+      )
+        pFileSlug = 'medium-voltage-cables';
+      else if (
+        normalizedCat === 'solarkabel' ||
+        normalizedCat === 'solar-cables' ||
+        normalizedCat === 'solar'
+      )
+        pFileSlug = 'solar-cables';
+
+      return pFileSlug === fileSlug;
+    });
 
     const productsWithTranslatedSlugs = await Promise.all(
       filteredProducts.map(async (p) => ({