Tenancy: realm and billing account

Vluna uses two distinct scopes. Do not mix them up.

Concepts

Concept	Identifier	Meaning
Realm	`realm_id`	Project boundary. All data is isolated by realm.
Billing account	`billing_account_id`	Account boundary for billing data and enforcement decisions.

Every request must include:

Account-scoped requests also include account context, typically via:

For public /api/v1 endpoints, the bearer token is typically issued for a principal and implicitly scopes the billing account.

Field	Typical source	Changes when
`realm_id`	app config	only when you switch environments (dev, staging, prod)
service key	server config	rotates over time
`principal_id`	your app request context	changes per customer
`billing_account_id`	your mapping table	changes per customer