Create a new city
Create a new city with its supported verticals. The city ID must be unique,
and the city code must also be unique. This endpoint validates all required
fields and formats before creating the city.
**Validation Rules:**
- id: lowercase letters, numbers, and hyphens only
- cityCode: uppercase letters and underscores only
- iataCode: exactly 3 uppercase letters
- scope: must include at least one valid vertical
