Adds 4 nullable columns to the users table so deployments that wire an
external billing system (e.g. velxio.dev with Odoo) have a place to cache
subscription status. Self-hosters never write these — defaults are safe
(no paid features unlock).
- models/user.py: is_paid_subscriber (bool, default false), subscription_status
(str|None), subscription_period_end (datetime|None), odoo_partner_id
(int|None, indexed).
- main.py: 4 ALTER TABLE statements appended to the legacy_migrations list
so existing deployments auto-migrate on next boot.
- schemas/auth.py: extend UserResponse with the 3 user-visible fields
(is_paid_subscriber, subscription_status, subscription_period_end). The
frontend useAuthStore already persists the whole UserResponse, so these
surface automatically without any frontend changes upstream.
odoo_partner_id stays internal — clients don't need it.
Zero behavioural change for existing OSS deployments.
5f0e7523ed