Align CMP Datamailer audience config with sandbox data

[alexeygrigorev]

Problem

CMP is configured with DATAMAILER_AUDIENCE=dtc-courses, but the Datamailer sandbox does not have an audience with slug dtc-courses. Calling:

GET /api/contacts/status?email=alexey@datatalks.club&audience=dtc-courses&client=dtc-courses

returns:

{"error": {"code": "validation_error", "fields": {"audience": "not_found"}}}

Transactional send still works because it is scoped by client/template and does not require the audience row.

What to decide

• Whether CMP should use DATAMAILER_AUDIENCE=datatalks-club with DATAMAILER_CLIENT=dtc-courses.
• Or whether Datamailer sandbox should create a dedicated dtc-courses audience.
• Then update CMP env/docs and seed/provisioning scripts accordingly.

Acceptance criteria

• manage.py datamailer_status alexey@datatalks.club --json works against sandbox.
• Contact status/history returns recent transactional messages for CMP users.
• Sandbox/provisioning keeps the expected audience/client rows present.