feat: add member since date handling across admin and member views

src/pages/admin/AdminStaff.js

@@ -242,12 +242,14 @@ const AdminStaff = () => {
             </div>
           ) : filteredUsers.length > 0 ? (
             <div className="space-y-4">
-              {filteredUsers.map((user) => (
-                <Card
-                  key={user.id}
-                  className="p-6 bg-background rounded-2xl border border-[var(--neutral-800)] hover:shadow-md transition-shadow"
-                  data-testid={`staff-card-${user.id}`}
-                >
+              {filteredUsers.map((user) => {
+                const joinedDate = user.member_since || user.created_at;
+                return (
+                  <Card
+                    key={user.id}
+                    className="p-6 bg-background rounded-2xl border border-[var(--neutral-800)] hover:shadow-md transition-shadow"
+                    data-testid={`staff-card-${user.id}`}
+                  >
                   <div className="flex justify-between items-start flex-wrap gap-4">
                     <div className="flex items-start gap-4 flex-1">
                       {/* Avatar */}
@@ -267,7 +269,7 @@ const AdminStaff = () => {
                         <div className="grid md:grid-cols-2 gap-2 text-sm text-brand-purple " style={{ fontFamily: "'Nunito Sans', sans-serif" }}>
                           <p>Email: {user.email}</p>
                           <p>Phone: {user.phone}</p>
-                          <p>Joined: {new Date(user.created_at).toLocaleDateString()}</p>
+                          <p>Joined: {joinedDate ? new Date(joinedDate).toLocaleDateString() : 'N/A'}</p>
                           {user.last_login && (
                             <p>Last Login: {new Date(user.last_login).toLocaleDateString()}</p>
                           )}
@@ -321,8 +323,9 @@ const AdminStaff = () => {
                       )}
                     </div>
                   </div>
-                </Card>
-              ))}
+                  </Card>
+                );
+              })}
             </div>
           ) : (
             <div className="text-center py-20">