feat(i18n): add validation strings for ValidationCard component

- Add validation section to en.json, zh.json, ja.json dictionaries
- Update ValidationCard to use useDictionary hook
- Replace all hardcoded English strings with i18n keys

lib/i18n/dictionaries/en.json

@@ -252,6 +252,24 @@
         "searchPlaceholder": "Search chats...",
         "noResults": "No chats found"
     },
+    "validation": {
+        "title": "Validate Diagram",
+        "capturing": "Capturing",
+        "validating": "Validating",
+        "validatingWithAttempt": "Validating ({attempt}/{max})",
+        "valid": "Valid",
+        "validWithWarnings": "Valid with Warnings",
+        "issuesFound": "Issues Found",
+        "error": "Error",
+        "skipped": "Skipped",
+        "capturedScreenshot": "Captured Screenshot:",
+        "issuesFoundLabel": "Issues Found:",
+        "suggestions": "Suggestions:",
+        "passedValidation": "Diagram passed visual validation - no issues detected.",
+        "improvementRequested": "Improvement requested - check the new diagram below",
+        "improveWithSuggestions": "Improve with Suggestions",
+        "regenerateWithFeedback": "Regenerate the diagram using the validation feedback"
+    },
     "modelConfig": {
         "title": "AI Model Configuration",
         "description": "Configure multiple AI providers and models",

lib/i18n/dictionaries/ja.json

@@ -252,6 +252,24 @@
         "searchPlaceholder": "チャットを検索...",
         "noResults": "チャットが見つかりません"
     },
+    "validation": {
+        "title": "ダイアグラムを検証",
+        "capturing": "キャプチャ中",
+        "validating": "検証中",
+        "validatingWithAttempt": "検証中 ({attempt}/{max})",
+        "valid": "有効",
+        "validWithWarnings": "有効（警告あり）",
+        "issuesFound": "問題が見つかりました",
+        "error": "エラー",
+        "skipped": "スキップ",
+        "capturedScreenshot": "キャプチャした画像：",
+        "issuesFoundLabel": "検出された問題：",
+        "suggestions": "提案：",
+        "passedValidation": "ダイアグラムは視覚検証に合格しました - 問題は検出されませんでした。",
+        "improvementRequested": "改善リクエスト済み - 下の新しいダイアグラムを確認してください",
+        "improveWithSuggestions": "提案で改善",
+        "regenerateWithFeedback": "検証フィードバックを使用してダイアグラムを再生成"
+    },
     "modelConfig": {
         "title": "AIモデル設定",
         "description": "複数のAIプロバイダーとモデルを設定",

lib/i18n/dictionaries/zh.json

@@ -252,6 +252,24 @@
         "searchPlaceholder": "搜索对话...",
         "noResults": "未找到对话"
     },
+    "validation": {
+        "title": "验证图表",
+        "capturing": "截图中",
+        "validating": "验证中",
+        "validatingWithAttempt": "验证中 ({attempt}/{max})",
+        "valid": "通过",
+        "validWithWarnings": "通过（有警告）",
+        "issuesFound": "发现问题",
+        "error": "错误",
+        "skipped": "已跳过",
+        "capturedScreenshot": "截图预览：",
+        "issuesFoundLabel": "发现的问题：",
+        "suggestions": "建议：",
+        "passedValidation": "图表通过视觉验证 - 未发现问题。",
+        "improvementRequested": "改进请求已发送 - 请查看下方新图表",
+        "improveWithSuggestions": "根据建议改进",
+        "regenerateWithFeedback": "使用验证反馈重新生成图表"
+    },
     "modelConfig": {
         "title": "AI 模型配置",
         "description": "配置多个 AI 提供商和模型",