Adds the system payment method for paying with EnakPoint
(docs/prd-point-coin.md F9, §8, §10.5, PC-303).
Migration 000094 allows the point type, keeps one per organization with a
partial unique index, creates it for every existing organization, and adds
a trigger that creates it for new ones, as the walk-in customer is. It adds
payments.points_used and point_value. Their CHECK is written so it can
never be NULL: the PRD form, (both NULL) OR (both > 0), is NULL for
points_used with a NULL point_value, which a CHECK lets through, so a
payment could have lost the value a refund depends on. A test caught it.
The API cannot create, delete or retype the EnakPoint method, nor turn
another method into one; that answers 400. Renaming it is allowed. The
method list takes the outlet from ?outlet_id= or the user's outlet and
leaves EnakPoint out when that outlet does not accept it, filtered in the
query so the count stays right. The organization-wide active list is
unchanged.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>