Improve authentication error handling

- Enhance error messages for authentication failures.

src/components/auth/RegisterForm.tsx

@@ -9,7 +9,7 @@ import { useToast } from "@/hooks/useToast.wrapper";
 import { verifyServerConnection } from "@/contexts/auth/auth.utils";
 
 interface RegisterFormProps {
-  signUp: (email: string, password: string, username: string) => Promise<{
+  signUp: (email: string, password: string) => Promise<{
     error: any;
     user: any;
   }>;
@@ -88,7 +88,7 @@ const RegisterForm: React.FC<RegisterFormProps> = ({
     setIsLoading(true);
     
     try {
-      const { error, user } = await signUp(email, password, username);
+      const { error, user } = await signUp(email, password);
       
       if (error) {
         setRegisterError(error.message || '알 수 없는 오류가 발생했습니다.');

src/contexts/auth/signInUtils.ts

@@ -11,7 +11,12 @@ export const signInWithDirectApi = async (email: string, password: string) => {
   try {
     // 로그인 API 엔드포인트 URL과 헤더 준비
     const supabaseUrl = supabase.auth.url;
-    const tokenUrl = `${supabaseUrl}/auth/v1/token?grant_type=password`;
+    // URL 경로 중복 방지를 위해 경로 확인 및 정규화
+    const baseUrl = supabaseUrl?.endsWith('/auth/v1') 
+      ? supabaseUrl 
+      : `${supabaseUrl}/auth/v1`;
+    
+    const tokenUrl = `${baseUrl}/token?grant_type=password`;
     const headers = {
       'Content-Type': 'application/json',
       'Authorization': `Bearer ${supabase.supabaseKey}`,
@@ -43,7 +48,7 @@ export const signInWithDirectApi = async (email: string, password: string) => {
       console.warn('API 경로를 찾을 수 없음 (404). 새 엔드포인트 시도 중...');
       
       // 대체 엔드포인트 시도 (/token 대신 /signin)
-      const signinUrl = `${supabaseUrl}/auth/v1/signin`;
+      const signinUrl = `${baseUrl}/signin`;
       
       try {
         const signinResponse = await fetch(signinUrl, {

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,