Billing may create its Events subscriptions (account export and deletion first; its account grants follow) (#263)

ddiff --git a/server/identity/principals.js b/server/identity/principals.js
iindex fea16bd4..8ee992f1 100644
---- a/server/identity/principals.js
++++ b/server/identity/principals.js
@@@ -46,6 +46,9 @@ const DEFAULT_GRANTS = [
      // Plan T16: Codes keeps the coding tasks people start on their own machines (run_tasks), so it answers account
      // export and deletion (ADR-033) and subscribes to them first; its account grants follow once it is subscribed.
      ['codes', 'events.subscription.manage', 'openvibe.events', []],
++    // Billing, the money ledger since 2026-10-17, answers account export and deletion (Billing#77) and subscribes to them
++    // at boot first; its account grants follow once it is subscribed.
++    ['billing', 'events.subscription.manage', 'openvibe.events', []],
      // The Workshop (ADR-054 §6): a creator gives a badge to "@name"; Inventory resolves the name to a subject.
      ['inventory', 'identity.subject.resolve', SELF_AUDIENCE, []],
      ...['inventory.item.read', 'inventory.item.list', 'inventory.equip.manage', 'inventory.item.grant', 'inventory.item.consume', 'inventory.definition.manage']