📝 Sync v3 docs and content across all nine languages

New shortcode sections, landing layout docs, agent skill sections,
v2→v3 upgrade instructions, translated homepages, and sample
article feature images.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

exampleSite/content/docs/content-examples/index.de.md

@@ -1,5 +1,6 @@
 ---
 title: "Inhaltsbeispiele"
+featureimage: "images/v3/content-examples.png"
 weight: 11
 draft: false
 description: "Alle verfügbaren Partials in Blowfish."