feat: complete fine-grained RBAC rules across all roles

- Restricted Agent view to own dashboard and hid management tabs.

- Allowed Managers to create teams and members but restricted them from editing roles or emails.

- Allowed Admins to update their own email via profile.

- Protected Admin roles from being modified by anyone other than Super Admins.

components/Layout.tsx

@@ -112,8 +112,12 @@ export const Layout: React.FC<{ children: React.ReactNode }> = ({ children }) =>
             {!isSuperAdmin && (
               <>
                 <SidebarItem to="/" icon={LayoutDashboard} label="Dashboard" collapsed={false} />
-                <SidebarItem to="/admin/users" icon={Users} label="Membros" collapsed={false} />
-                <SidebarItem to="/admin/teams" icon={Building2} label="Times" collapsed={false} />
+                {currentUser.role !== 'agent' && (
+                  <>
+                    <SidebarItem to="/admin/users" icon={Users} label="Membros" collapsed={false} />
+                    <SidebarItem to="/admin/teams" icon={Building2} label="Times" collapsed={false} />
+                  </>
+                )}
               </>
             )}