Update Supabase connection tests

Improve error handling for REST API and database connection tests.

src/components/supabase/ProxyRecommendationAlert.tsx

@@ -8,24 +8,25 @@ interface ProxyRecommendationAlertProps {
 }
 
 const ProxyRecommendationAlert: React.FC<ProxyRecommendationAlertProps> = ({ errors }) => {
-  const hasProxyRecommendation = errors.some(err => 
-    err.includes('프록시 사용 시 정상 작동합니다') || 
-    err.includes('프록시를 선택해보세요')
+  const hasCorsError = errors.some(err => 
+    err.includes('CORS') || 
+    err.includes('Failed to fetch') ||
+    err.includes('프록시 사용시 정상 작동') || 
+    err.includes('프록시를 활성화')
   );
   
-  if (!hasProxyRecommendation || errors.length === 0) return null;
-  
-  const recommendationMessage = errors.find(err => 
-    err.includes('프록시 사용 시 정상 작동합니다') || 
-    err.includes('프록시를 선택해보세요')
-  );
+  if (!hasCorsError || errors.length === 0) return null;
   
   return (
     <Alert className="bg-amber-50 border-amber-200 mt-3">
       <AlertCircle className="h-4 w-4 text-amber-600" />
-      <AlertTitle className="text-amber-800 text-xs font-medium">프록시 변경 권장</AlertTitle>
+      <AlertTitle className="text-amber-800 text-xs font-medium">CORS 오류 감지됨</AlertTitle>
       <AlertDescription className="text-amber-700 text-xs">
-        {recommendationMessage}
+        <p>HTTP URL에 대한 브라우저 보안 제한으로 인해 연결에 실패했습니다.</p>
+        <ul className="list-disc pl-4 mt-1">
+          <li className="mt-1">CORS 프록시를 활성화하고 프록시 유형을 변경해보세요.</li>
+          <li className="mt-1">또는 HTTPS URL로 변경하는 것을 고려하세요.</li>
+        </ul>
       </AlertDescription>
     </Alert>
   );

src/components/supabase/ProxyTypeSelector.tsx

@@ -24,6 +24,7 @@ const ProxyTypeSelector: React.FC<ProxyTypeSelectorProps> = ({
           <SelectItem value="thingproxy">thingproxy.freeboard.io</SelectItem>
           <SelectItem value="allorigins">allorigins.win</SelectItem>
           <SelectItem value="cors-anywhere">cors-anywhere.herokuapp.com</SelectItem>
+          <SelectItem value="cloudflare">Cloudflare Workers 프록시</SelectItem>
         </SelectContent>
       </Select>
       <p className="text-xs text-gray-500 mt-1">