feat(auth): implement role-based access control and user management features

frontend/auth.ts

@@ -22,11 +22,12 @@ export const { handlers, auth, signIn, signOut } = NextAuth({
             }),
           });
           if (!res.ok) return null;
-          const data = await res.json() as { accessToken: string; userId: number; username: string };
+          const data = await res.json() as { accessToken: string; userId: number; username: string; role: string };
           return {
             id: String(data.userId),
             name: data.username,
             accessToken: data.accessToken,
+            role: data.role,
           };
         } catch {
           return null;
@@ -40,6 +41,7 @@ export const { handlers, auth, signIn, signOut } = NextAuth({
         token.accessToken = (user as any).accessToken as string;
         token.userId = Number(user.id);
         token.username = user.name ?? '';
+        token.role = (user as any).role as string;
       }
       return token;
     },
@@ -47,6 +49,7 @@ export const { handlers, auth, signIn, signOut } = NextAuth({
       session.accessToken = token.accessToken as string;
       session.user.id = String(token.userId);
       session.user.name = token.username as string;
+      (session.user as any).role = token.role as string;
       return session;
     },
   },