feat: implement authentication flow with login page, middleware protection, and session-based role management

src/lib/auth.ts

@@ -0,0 +1,19 @@
+export const isAuthenticated = (): boolean => {
+  return typeof window !== 'undefined' && !!sessionStorage.getItem('authToken');
+};
+
+export const getUserRole = (): string | null => {
+  return typeof window !== 'undefined' ? sessionStorage.getItem('userRole') : null;
+};
+
+export const getUserName = (): string | null => {
+  return typeof window !== 'undefined' ? sessionStorage.getItem('userName') : null;
+};
+
+export const logout = () => {
+  if (typeof window !== 'undefined') {
+    sessionStorage.removeItem('authToken');
+    sessionStorage.removeItem('userRole');
+    sessionStorage.removeItem('userName');
+  }
+};