fix: OpenAI API 키 수정 및 에러 로깅 개선

- Vault에서 올바른 OpenAI API 키 가져와 워커 시크릿 업데이트
- 에러 응답에 details 필드 추가 (디버깅용)
- AI 응답 로깅 추가

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

src/index.ts

@@ -806,9 +806,11 @@ async function handleRecommend(
     return jsonResponse(response, 200, corsHeaders);
   } catch (error) {
     console.error('[Recommend] Error:', error);
+    console.error('[Recommend] Error stack:', error instanceof Error ? error.stack : 'No stack');
     return jsonResponse(
       {
         error: 'Failed to generate recommendations',
+        details: error instanceof Error ? error.message : 'Unknown error',
         request_id: requestId,
       },
       500,
@@ -1634,9 +1636,11 @@ The option with the LOWEST TOTAL MONTHLY COST (including bandwidth) should have
     const response = openaiResult.choices[0]?.message?.content || '';
 
     console.log('[AI] Response received from OpenAI, length:', response.length);
+    console.log('[AI] Raw response preview:', response.substring(0, 500));
 
     // Parse AI response
     const aiResult = parseAIResponse(response);
+    console.log('[AI] Parsed recommendations count:', aiResult.recommendations.length);
 
     // Pre-index VPS benchmarks by provider for O(1) lookups
     const vpsByProvider = new Map<string, VPSBenchmark[]>();