fix(docs): restore stage-1 locale sidebars

docs/ja-jp/stage-1/ai-capabilities-through-games/index.md

@@ -14,7 +14,7 @@ import { relatedArticlesMap } from '@theme/data/relatedArticles'
 
 const duration = '約 <strong>4 時間</strong>、複数回に分けて完了可能'
 const relatedArticles =
-  relatedArticlesMap['zh-cn/stage-1/ai-capabilities-through-games'] ?? []
+  relatedArticlesMap['ja-jp/stage-1/ai-capabilities-through-games'] ?? []
 </script>
 
 ## 本章のガイド

docs/ja-jp/stage-1/integrating-ai-capabilities/index.md

@@ -8,7 +8,7 @@ import { relatedArticlesMap } from '@theme/data/relatedArticles'
 
 const duration = '約 <strong>1 日</strong>'
 const relatedArticles =
-  relatedArticlesMap['zh-cn/stage-1/integrating-ai-capabilities'] ?? []
+  relatedArticlesMap['ja-jp/stage-1/integrating-ai-capabilities'] ?? []
 </script>
 
 # 初級四：プロトタイプに AI 能力を注入する

docs/ja-jp/stage-1/introduction-to-ai-ide/index.md

@@ -12,7 +12,7 @@ import { relatedArticlesMap } from '@theme/data/relatedArticles'
 
 const duration = '約 <strong>1 日</strong>、複数回に分けても可'
 const relatedArticles =
-  relatedArticlesMap['zh-cn/stage-1/introduction-to-ai-ide'] ?? []
+  relatedArticlesMap['ja-jp/stage-1/introduction-to-ai-ide'] ?? []
 </script>
 
 <ChapterIntroduction :duration="duration" :tags="['ローカル開発環境構築', 'IDE と AI IDE', '効率的な開発テクニック']" coreOutput="1つの自作ミニゲーム" expectedOutput="Trae を使用して制作">