docs: add native Japanese translation of ECC documentation (ja-JP)

Translate everything-claude-code repository to Japanese including:
- 17 root documentation files
- 60 agent documentation files
- 80 command documentation files
- 99 rule files across 18 language directories (common, angular, arkts, cpp, csharp, dart, fsharp, golang, java, kotlin, perl, php, python, ruby, rust, swift, typescript, web)
- 199 skill documentation files

Total: 455 files translated to Japanese with:
- Consistent terminology glossary applied throughout
- YAML field names preserved in English (name, description, etc.)
- Code blocks and examples untouched (comments translated)
- Markdown structure and relative links preserved
- Professional translation maintaining technical accuracy

This translation expands ECC accessibility to Japanese-speaking developers and teams.

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

docs/ja-JP/rules/kotlin/hooks.md

@@ -0,0 +1,17 @@
+---
+paths:
+  - "**/*.kt"
+  - "**/*.kts"
+  - "**/build.gradle.kts"
+---
+# Kotlin フック
+
+> このファイルは [common/hooks.md](../common/hooks.md) を Kotlin 固有のコンテンツで拡張します。
+
+## PostToolUse フック
+
+`~/.claude/settings.json` で設定:
+
+- **ktfmt/ktlint**: 編集後に `.kt` と `.kts` ファイルを自動フォーマット
+- **detekt**: Kotlin ファイル編集後に静的解析を実行
+- **./gradlew build**: 変更後にコンパイルを検証