Improve authentication error handling

- Enhance error messages for authentication failures.

src/contexts/auth/signUpUtils.ts

@@ -12,8 +12,13 @@ export const signUpWithDirectApi = async (email: string, password: string) => {
     const supabaseUrl = supabase.auth.url;
     const supabaseKey = localStorage.getItem('supabase_key') || supabase.supabaseKey;
     
+    // URL 경로 중복 방지를 위해 경로 확인 및 정규화
+    const baseUrl = supabaseUrl?.endsWith('/auth/v1') 
+      ? supabaseUrl 
+      : `${supabaseUrl}/auth/v1`;
+    
     // 회원가입 API 엔드포인트 및 헤더 설정
-    const signUpUrl = `${supabaseUrl}/auth/v1/signup`;
+    const signUpUrl = `${baseUrl}/signup`;
     const headers = {
       'Content-Type': 'application/json',
       'apikey': supabaseKey,