Promote Smartadvocate Intake Draft

Promote a draft intake: create the contact and case in SmartAdvocate.

Runs the shared sixteen-step promoter — the same one the Celery auto-push path uses — with the (user-edited) fields from the request. Dedup is re-checked at promote time since the draft's snapshot may be stale:

• If the caller's phone matches an existing synced SA contact, only the case is created, attached via PlaintiffContactID.
• If the matched contact already has a case with the same incident date, the promote is refused (409) unless override_duplicates is set.
• If staff opened a case for this caller shortly before or after the call (read live from SA), the intake merges into it: nothing the firm entered is overwritten and our facts are appended. merge_into_case_id or force_new_case overrides that choice; an undecidable match is 409.

Only contact and case creation are fatal. Every enrichment step (plaintiff role, injuries, insurance, providers, vehicle, tags, status, intake fields, call log) records its own outcome in the response's promote_steps, so a case is never lost to one rejected id — the failed steps can be re-run via retry-steps.