feat(backend): implement create admin API (ticket #97)

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/src/routes/user/dto/create_admin.dto.ts

@@ -1,4 +1,10 @@
-import { OmitType } from "@nestjs/swagger";
+import { PickType } from "@nestjs/swagger";
 import { CreateUserDto } from "./create_user.dto";
 
-export class CreateAdminDto extends OmitType(CreateUserDto, ['role'] as const) {}
+export class CreateAdminDto extends PickType(CreateUserDto, [
+  'nom',
+  'prenom',
+  'email',
+  'password',
+  'telephone'
+] as const) {}