ONLY call this when the user has chosen a provider and wants to be contacted —
it sends a real request to the locksmith. Provide a phone (preferred) or email
so the locksmith can reach the customer. Returns a reference id (HL-####); the
locksmith confirms availability, price, and ETA directly.

Args:
    locksmith_id: id from search_locksmiths / get_locksmith.
    name:         Customer name.
    phone:        Customer phone (preferred). Phone OR email is required.
    email:        Customer email (alternative to phone).
    zip:          5-digit ZIP of the job (improves routing/records).
    service:      Job type, e.g. "lockout", "automotive".
    details:      Free-text description of the job.
    urgency:      e.g. "emergency", "today".