Update Enquiry

Update an existing enquiry’s fields and/or attribution data.

At least one of fields / tracking_data must be present.

• fields.*.name required string; fields.*.value must be present and a string (stringify numbers/booleans). An explicit null is stored as an empty string, matching the create path.
• tracking_data replaces the whole set — an empty array clears it, and is only valid alongside a fields payload.
• tracking_data rows follow the same rules as POST /enquiries: parameter required string; value / path / session_at nullable. session_at is optional. Scalar values (numbers, booleans) are coerced to strings first, so a payload accepted on create is never rejected on update.

Editing an enquiry bumps its updated_at, so the change surfaces on the next GET /enquiries?updated_after=... poll.

Success is HTTP 201.