support reset evaluation prompt

src/app/admin/prompts/evaluation/[id]/page.tsx

@@ -20,6 +20,7 @@ export default function EditEvaluationPromptPage() {
   const [name, setName] = useState('');
   const [description, setDescription] = useState('');
   const [systemPrompt, setSystemPrompt] = useState('');
+  const [resetting, setResetting] = useState(false);
 
   // Load prompt data
   useEffect(() => {
@@ -82,6 +83,33 @@ export default function EditEvaluationPromptPage() {
     }
   };
 
+  const handleReset = async () => {
+    if (!confirm('確定要重設為預設值嗎？這將覆蓋目前的所有變更。')) {
+      return;
+    }
+
+    setResetting(true);
+    setError(null);
+
+    try {
+      const response = await adminFetch(`/api/admin/evaluation-prompts/${promptId}/default`);
+
+      if (!response.ok) {
+        const data = await response.json();
+        throw new Error(data.error || '無法取得預設值');
+      }
+
+      const defaultPrompt = await response.json();
+      setName(defaultPrompt.name);
+      setDescription(defaultPrompt.description || '');
+      setSystemPrompt(defaultPrompt.systemPrompt);
+    } catch (err) {
+      setError(err instanceof Error ? err.message : '重設失敗');
+    } finally {
+      setResetting(false);
+    }
+  };
+
   if (loading) {
     return (
       <div className="min-h-screen bg-gray-50 p-4 md:p-8">
@@ -237,6 +265,11 @@ export default function EditEvaluationPromptPage() {
             >
               評估系統提示詞 <span className="text-red-500">*</span>
             </label>
+            <div className="mb-3 bg-amber-50 border border-amber-200 rounded-lg p-3">
+              <p className="text-sm text-amber-800">
+                <span className="font-semibold">⚠️ 重要：</span>提示詞必須要求 AI 回傳有效的 JSON 格式。如果回應格式不正確，系統將無法解析評估結果。
+              </p>
+            </div>
             <textarea
               id="systemPrompt"
               value={systemPrompt}
@@ -259,9 +292,18 @@ export default function EditEvaluationPromptPage() {
               取消
             </Link>
 
+            <button
+              type="button"
+              onClick={handleReset}
+              disabled={resetting || saving}
+              className="flex-1 sm:flex-none px-6 py-2 text-center border border-orange-300 text-orange-700 rounded-lg hover:bg-orange-50 disabled:bg-gray-100 disabled:text-gray-400 disabled:border-gray-200 disabled:cursor-not-allowed transition-colors"
+            >
+              {resetting ? '重設中...' : '重設為預設'}
+            </button>
+
             <button
               type="submit"
-              disabled={saving}
+              disabled={saving || resetting}
               className="flex-1 sm:flex-none px-6 py-2 bg-blue-600 text-white rounded-lg hover:bg-blue-700 disabled:bg-gray-400 disabled:cursor-not-allowed transition-colors"
             >
               {saving ? '儲存中...' : '儲存變更'}

src/app/api/admin/evaluation-prompts/[id]/default/route.ts

@@ -0,0 +1,30 @@
+import { NextResponse } from 'next/server';
+import { withAdminAuthParams } from '@/lib/auth';
+import { getEvaluationPromptConfigFallback } from '@/lib/prompts/evaluation-prompts';
+
+/**
+ * GET /api/admin/evaluation-prompts/:id/default
+ * Get the default evaluation prompt from TypeScript files (fallback)
+ * Requires admin authentication
+ */
+export const GET = withAdminAuthParams<{ id: string }>(
+  async (_request, _auth, { params }) => {
+    const { id } = await params;
+
+    const defaultPrompt = getEvaluationPromptConfigFallback(id);
+
+    if (!defaultPrompt) {
+      return NextResponse.json(
+        { error: `No default evaluation prompt found for: ${id}` },
+        { status: 404 }
+      );
+    }
+
+    return NextResponse.json({
+      id: defaultPrompt.id,
+      name: defaultPrompt.name,
+      description: defaultPrompt.description,
+      systemPrompt: defaultPrompt.systemPrompt,
+    });
+  }
+);