📝 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/series/index.de.md

@@ -1,5 +1,6 @@
 ---
 title: "Serien"
+featureimage: "images/v3/series.png"
 weight: 12
 draft: false
 description: "Erfahren Sie, wie Sie Artikel zu einer Serie gruppieren."

exampleSite/content/docs/series/index.es.md

@@ -1,5 +1,6 @@
 ---
 title: "Series"
+featureimage: "images/v3/series.png"
 weight: 12
 draft: false
 description: "Aprende cómo agrupar artículos en una serie."

exampleSite/content/docs/series/index.fr.md

@@ -1,5 +1,6 @@
 ---
 title: "Séries"
+featureimage: "images/v3/series.png"
 weight: 12
 draft: false
 description: "Apprenez à regrouper des articles dans une série."

exampleSite/content/docs/series/index.it.md

@@ -1,5 +1,6 @@
 ---
 title: "Series"
+featureimage: "images/v3/series.png"
 weight: 12
 draft: false
 description: "Learn how to group articles under a series."

exampleSite/content/docs/series/index.ja.md

@@ -1,5 +1,6 @@
 ---
 title: "シリーズ"
+featureimage: "images/v3/series.png"
 weight: 12
 draft: false
 description: "記事をシリーズの下にグループ化する方法を学びます。"

exampleSite/content/docs/series/index.pt-br.md

@@ -1,5 +1,6 @@
 ---
 title: "Séries"
+featureimage: "images/v3/series.png"
 weight: 12
 draft: false
 description: "Aprenda como agrupar artigos em uma série."

exampleSite/content/docs/series/index.pt-pt.md

@@ -1,5 +1,6 @@
 ---
 title: "Séries"
+featureimage: "images/v3/series.png"
 weight: 12
 draft: false
 description: "Aprenda como agrupar artigos numa série."

exampleSite/content/docs/series/index.zh-cn.md

@@ -1,5 +1,6 @@
 ---
 title: "系列"
+featureimage: "images/v3/series.png"
 weight: 12
 draft: false
 description: "了解如何将文章分组到系列中。"