Update user profile to allow optional email and correct name updates

Fix bug where email was mandatory on user profile updates and ensure last name field updates correctly.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: a8a78c07-e900-425c-a577-5b4c5894379d
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/1957c339-2757-4d1f-8e92-e9f71a1ce58e/a8a78c07-e900-425c-a577-5b4c5894379d/vetH0Gp

client/src/pages/Users.tsx

@@ -917,14 +917,13 @@ export default function UsersPage() {
               </div>
 
               <div>
-                <Label htmlFor="edit-email">Email *</Label>
+                <Label htmlFor="edit-email">Email</Label>
                 <Input
                   id="edit-email"
                   type="email"
                   value={editForm.email}
                   onChange={(e) => setEditForm({...editForm, email: e.target.value})}
-                  placeholder="email@exemple.com"
-                  required
+                  placeholder="email@exemple.com (optionnel)"
                 />
               </div>