feat: skaffold progressive billing support

Author: turip

.agents/skills/charges/SKILL.md

@@ -124,6 +124,10 @@ Important rules:
 - usage-based exposes its billing line engine from `usagebased.Service.GetLineEngine()`; register that returned engine instead of reusing the service type directly
 - flat-fee now follows the same pattern: `flatfee.Service.GetLineEngine()` returns the engine owned by the service package
 - because flat-fee owns its line engine, `flatfee/service.New(...)` requires a `rating.Service`; forgetting that dependency breaks app/test wiring with `rating service cannot be null`
+- for usage-based realization creation, validate at the run-creation boundary (`usagebased/service/run.CreateRatedRunInput.Validate`) that `Charge.State.CurrentRealizationRunID` is nil before creating a new run; keep the line-engine-side early return too so `InvoicePendingLines` fails with the charge-specific validation error at the billing boundary. In both places, key the guard off `CurrentRealizationRunID`, not a specific status prefix such as `partial_invoice`
+- usage-based payment handling is intentionally different from flat-fee and credit-purchase: the usage-based state machine owns realization only, while the usage-based line engine/run service records payment authorization/settlement directly on historical runs and only re-enters the state machine through an aggregate trigger (for example `all_payments_settled`) once all invoiced runs on the charge are settled. Do not apply this rule generically to flat-fee or credit-purchase; those charge types may still keep payment states inside their own state machines.
+- usage-based invoice branches should read in this order: `started -> waiting_for_collection -> processing -> issuing -> completed`, then auto-advance out of the branch. Keep `invoice_issued` as the boundary between `processing` and `issuing`, run `FinalizeInvoiceRun(...)` from the `issuing` state, and let `completed` be the last branch-local status before `next` returns a partial invoice to `active` or moves a final invoice to `active.awaiting_payment_settlement`
+- when adding or renaming usage-based detailed statuses, remember that `status_detailed` is an Ent enum for `ChargeUsageBased`; run `make generate` so the generated enum validators and migrate schema include the new values before trusting state-machine changes
 
 Operational consequence:
 

openmeter/billing/charges/meta/triggers.go

@@ -5,10 +5,10 @@ import "github.com/qmuntal/stateless"
 type Trigger = stateless.Trigger
 
 var (
-	TriggerNext                     Trigger = "next"
-	TriggerInvoiceCreated           Trigger = "invoice_created"
-	TriggerCollectionCompleted      Trigger = "collection_completed"
-	TriggerInvoiceIssued            Trigger = "invoice_issued"
-	TriggerInvoicePaymentAuthorized Trigger = "invoice_payment_authorized"
-	TriggerInvoicePaymentSettled    Trigger = "invoice_payment_settled"
+	TriggerNext                  Trigger = "next"
+	TriggerPartialInvoiceCreated Trigger = "partial_invoice_created"
+	TriggerFinalInvoiceCreated   Trigger = "final_invoice_created"
+	TriggerCollectionCompleted   Trigger = "collection_completed"
+	TriggerInvoiceIssued         Trigger = "invoice_issued"
+	TriggerAllPaymentsSettled    Trigger = "all_payments_settled"
 )

openmeter/billing/charges/service/invoicable_test.go

@@ -1191,7 +1191,7 @@ func (s *InvoicableChargesTestSuite) TestUsageBasedCreditThenInvoiceLifecycle()
 		}, invoice.Totals)
 
 		usageBasedCharge := s.mustGetUsageBasedChargeByID(usageBasedChargeID)
-		s.Equal(usagebased.StatusActiveFinalRealizationCompleted, usageBasedCharge.Status)
+		s.Equal(usagebased.StatusActiveFinalRealizationProcessing, usageBasedCharge.Status)
 		s.NotNil(usageBasedCharge.State.CurrentRealizationRunID)
 		s.Len(usageBasedCharge.Realizations, 1)
 
@@ -1236,7 +1236,7 @@ func (s *InvoicableChargesTestSuite) TestUsageBasedCreditThenInvoiceLifecycle()
 		s.Equal(1, invoiceUsageAccruedCallback.nrInvocations)
 
 		usageBasedCharge := s.mustGetUsageBasedChargeByID(usageBasedChargeID)
-		s.Equal(usagebased.StatusActivePaymentPending, usageBasedCharge.Status)
+		s.Equal(usagebased.StatusActiveAwaitingPaymentSettlement, usageBasedCharge.Status)
 		s.Nil(usageBasedCharge.State.CurrentRealizationRunID)
 		s.Nil(usageBasedCharge.State.AdvanceAfter)
 		s.Len(usageBasedCharge.Realizations, 1)
@@ -1258,7 +1258,7 @@ func (s *InvoicableChargesTestSuite) TestUsageBasedCreditThenInvoiceLifecycle()
 		s.Equal(invoiceUsageAccruedCallback.id, finalRun.InvoiceUsage.LedgerTransaction.TransactionGroupID)
 	})
 
-	s.Run("#7 payment authorization moves charge to active authorized", func() {
+	s.Run("#7 payment authorization keeps charge awaiting settlement", func() {
 		defer s.UsageBasedTestHandler.Reset()
 
 		authorizedCallback := newCountedLedgerTransactionCallback[usagebased.OnPaymentAuthorizedInput]()
@@ -1279,7 +1279,7 @@ func (s *InvoicableChargesTestSuite) TestUsageBasedCreditThenInvoiceLifecycle()
 		s.Equal(1, authorizedCallback.nrInvocations)
 
 		usageBasedCharge := s.mustGetUsageBasedChargeByID(usageBasedChargeID)
-		s.Equal(usagebased.StatusActiveAuthorized, usageBasedCharge.Status)
+		s.Equal(usagebased.StatusActiveAwaitingPaymentSettlement, usageBasedCharge.Status)
 		s.Len(usageBasedCharge.Realizations, 1)
 
 		finalRun := usageBasedCharge.Realizations[0]
@@ -1465,7 +1465,7 @@ func (s *InvoicableChargesTestSuite) TestUsageBasedCreditThenInvoiceFullyCredite
 		}, invoice.Totals)
 
 		usageBasedCharge := s.mustGetUsageBasedChargeByID(usageBasedChargeID)
-		s.Equal(usagebased.StatusActiveFinalRealizationCompleted, usageBasedCharge.Status)
+		s.Equal(usagebased.StatusActiveFinalRealizationProcessing, usageBasedCharge.Status)
 		s.NotNil(usageBasedCharge.State.CurrentRealizationRunID)
 		s.Len(usageBasedCharge.Realizations, 1)
 
@@ -1491,7 +1491,7 @@ func (s *InvoicableChargesTestSuite) TestUsageBasedCreditThenInvoiceFullyCredite
 		s.Equal(0, invoiceUsageAccruedCallback.nrInvocations)
 
 		usageBasedCharge := s.mustGetUsageBasedChargeByID(usageBasedChargeID)
-		s.Equal(usagebased.StatusActivePaymentPending, usageBasedCharge.Status)
+		s.Equal(usagebased.StatusActiveAwaitingPaymentSettlement, usageBasedCharge.Status)
 		s.Nil(usageBasedCharge.State.CurrentRealizationRunID)
 		s.Nil(usageBasedCharge.State.AdvanceAfter)
 		s.Len(usageBasedCharge.Realizations, 1)