refactor: update admin manager role credentials and simplify login password UI

src/app/login/page.tsx

@@ -7,7 +7,7 @@ import { Zap, ArrowRight, Bike, Wallet, Shield, Users, Calculator, Store, Truck
 
 const demoUsers = [
   { email: 'superadmin@jaiben.com', role: 'super_admin', label: 'Super Admin', icon: Shield, color: 'bg-accent' },
-  { email: 'admin@jaiben.com', role: 'admin', label: 'Admin Manager', icon: Users, color: 'bg-blue-500' },
+  { email: 'adminmanager@jaiben.com', role: 'admin_manager', label: 'Admin Manager', icon: Users, color: 'bg-blue-500' },
   { email: 'staff@jaiben.com', role: 'staff', label: 'Front Desk', icon: Users, color: 'bg-purple-500' },
   { email: 'accountant@jaiben.com', role: 'accountant', label: 'Accountant', icon: Calculator, color: 'bg-green-500' },
   { email: 'investor@email.com', role: 'investor', label: 'Investor', icon: Wallet, color: 'bg-amber-500' },
@@ -35,10 +35,9 @@ export default function LoginPage() {
       sessionStorage.setItem('userRole', user.role);
       sessionStorage.setItem('userName', user.name);
 
-switch (user.role) {
+      switch (user.role) {
         case 'super_admin':
-        case 'admin':
-        case 'manager':
+        case 'admin_manager':
         case 'staff':
           router.push('/admin');
           break;
@@ -63,24 +62,23 @@ switch (user.role) {
     } else {
       setError('Invalid email or password. Try demo123');
     }
-    
+
     setLoading(false);
   };
 
   const handleQuickLogin = async (userEmail: string) => {
     setLoading(true);
     await new Promise(resolve => setTimeout(resolve, 500));
-    
+
     const user = users.find(u => u.email === userEmail);
     if (user) {
       sessionStorage.setItem('authToken', 'demo-token');
       sessionStorage.setItem('userRole', user.role);
       sessionStorage.setItem('userName', user.name);
-      
+
       switch (user.role) {
         case 'super_admin':
-        case 'admin':
-        case 'manager':
+        case 'admin_manager':
         case 'staff':
           router.push('/admin');
           break;
@@ -143,7 +141,7 @@ switch (user.role) {
 
             <div>
               <label htmlFor="password" className="block text-sm font-medium text-slate-300 mb-2">
-                Password <span className="text-slate-500 text-xs">(demo: demo123)</span>
+                Password
               </label>
               <input
                 type="password"