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/golang/security.md

@@ -0,0 +1,34 @@
+---
+paths:
+  - "**/*.go"
+  - "**/go.mod"
+  - "**/go.sum"
+---
+# Go セキュリティ
+
+> このファイルは [common/security.md](../common/security.md) を Go 固有のコンテンツで拡張します。
+
+## シークレット管理
+
+```go
+apiKey := os.Getenv("OPENAI_API_KEY")
+if apiKey == "" {
+    log.Fatal("OPENAI_API_KEY not configured")
+}
+```
+
+## セキュリティスキャン
+
+- **gosec** を使用して静的セキュリティ解析を実行:
+  ```bash
+  gosec ./...
+  ```
+
+## Context とタイムアウト
+
+タイムアウト制御には常に `context.Context` を使用する:
+
+```go
+ctx, cancel := context.WithTimeout(ctx, 5*time.Second)
+defer cancel()
+```