feat(admin): support user profile editing, password resetting, and email column with search

- Add UpdateUser API and logics supporting nickname, email, admin flag modification, and password reset.
- Relocate user delete button and confirmation Alert into the EditUserModal.
- Optimize admin Switch change to trigger instant API request with rollback support.
- Fix missing email field in edit form initialization by fetching full profile metadata.
- Render email column in users list and support email-based filtering in UserFilterBar.
- Remove hardcoded styles and sizes from Switch components to follow global theme.

frontend/app/(main)/admin/push/components/events-tab.tsx

@@ -327,7 +327,7 @@ export function EventsTab() {
                     <Switch
                       checked={event.enabled}
                       onCheckedChange={() => toggleEventMutation.mutate(event.id)}
-                      className="scale-75 data-[state=checked]:bg-green-600 h-4 w-7"
+                      className="scale-75"
                     />
                   </TableCell>
                   <TableCell className="sticky right-0 text-center bg-background z-10 py-1" onClick={(e) => e.stopPropagation()}>

frontend/app/(main)/admin/push/components/settings-tab.tsx

@@ -324,7 +324,7 @@ export function SettingsTab() {
                           }
                         })
                       }}
-                      className="scale-75 data-[state=checked]:bg-green-600 h-4 w-7"
+                      className="scale-75"
                     />
                   </TableCell>
                   <TableCell className="sticky right-0 text-center bg-background z-10 py-1" onClick={(e) => e.stopPropagation()}>