feat(loyalty): give new balances their expiry

Every lot now gets its expiry when it is created (docs/prd-point-coin.md
F12, PC-502), where it used to never expire until note N4 was settled:

- EARN and an ADJUSTMENT that adds: ComputeExpiry of the organization's
  settings for that currency, from the moment received.
- EXCHANGE_IN: the sooner of the EnakCoin lot's expiry and when EnakPoint
  received now expire (F4).
- PAYMENT_REFUND: the expiry of the lot the EnakPoint came from, but at
  least seven days from the refund (N4, decided). A lot that never expired
  stays so.
- TRANSFER_IN: unchanged, exactly the sender's expiry.

Turning expiry on for a currency for the first time dates every lot of the
organization that still holds something and has no expiry, MIGRATION lots
included, in the same transaction as the setting: a full period from now
when ROLLING, the second fixed date on or after today when FIXED_DATE, so
no customer loses a balance soon after the rule is announced (N4,
decided). Turning it off leaves dated lots as they are. PUT
/marketing/loyalty-settings reports these as expiry_activations (currency,
lots, amount, expires_at); a dry run counts them without dating anything.

The earning processor now also reads the organization settings, and the
wallet admin processor takes the settings reader.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/processor/earning_processor.go

@@ -36,17 +36,25 @@ type outletSettingsReader interface {
 	Outlet(ctx context.Context, outletID uuid.UUID) (*models.OutletLoyaltySettings, error)
 }
 
+// earningSettingsReader gives the outlet's earning settings and the organization's
+// expiry. LoyaltySettingsProcessor is one.
+type earningSettingsReader interface {
+	outletSettingsReader
+	organizationSettingsReader
+}
+
 // EarningProcessor credits EnakPoint and EnakCoin for paid orders
 // (docs/prd-point-coin.md F3).
 type EarningProcessor struct {
 	orders   repository.EarningRepository
-	settings outletSettingsReader
+	settings earningSettingsReader
+	now      func() time.Time
 	wallet   *WalletProcessor
 	tx       TxRunner
 }
 
-func NewEarningProcessor(orders repository.EarningRepository, settings outletSettingsReader, wallet *WalletProcessor, tx TxRunner) *EarningProcessor {
-	return &EarningProcessor{orders: orders, settings: settings, wallet: wallet, tx: tx}
+func NewEarningProcessor(orders repository.EarningRepository, settings earningSettingsReader, wallet *WalletProcessor, tx TxRunner) *EarningProcessor {
+	return &EarningProcessor{orders: orders, settings: settings, wallet: wallet, tx: tx, now: time.Now}
 }
 
 // OnOrderPaid is called once an order has become fully paid and the payment has
@@ -87,6 +95,12 @@ func (p *EarningProcessor) EarnForOrder(ctx context.Context, orderID uuid.UUID)
 		return &EarningOutcome{Skipped: EarningSkipNothingToEarn}, nil
 	}
 
+	orgSettings, err := p.settings.Organization(ctx, order.OrganizationID)
+	if err != nil {
+		return nil, err
+	}
+	receivedAt := p.now()
+
 	outcome := &EarningOutcome{}
 	err = p.tx.WithTransaction(ctx, func(ctx context.Context) error {
 		for _, c := range []struct {
@@ -101,19 +115,24 @@ func (p *EarningProcessor) EarnForOrder(ctx context.Context, orderID uuid.UUID)
 				continue
 			}
 			outletID := order.OutletID
-			res, err := p.wallet.Credit(ctx, WalletCreditInput{WalletEntry: WalletEntry{
-				CustomerID:     *order.CustomerID,
-				Currency:       c.currency,
-				Type:           constants.WalletTxTypeEarn,
-				Amount:         c.line.Amount,
-				ReferenceType:  constants.WalletRefTypeOrder,
-				ReferenceID:    order.ID,
-				OutletID:       &outletID,
-				Description:    earningDescription(order),
-				Metadata:       result.Metadata(c.line),
-				IdempotencyKey: fmt.Sprintf("earn:%s:%s", order.ID, c.currency),
-				// Lots never expire until the expiry model is decided (F12, note N4).
-			}})
+			res, err := p.wallet.Credit(ctx, WalletCreditInput{
+				WalletEntry: WalletEntry{
+					CustomerID:     *order.CustomerID,
+					Currency:       c.currency,
+					Type:           constants.WalletTxTypeEarn,
+					Amount:         c.line.Amount,
+					ReferenceType:  constants.WalletRefTypeOrder,
+					ReferenceID:    order.ID,
+					OutletID:       &outletID,
+					Description:    earningDescription(order),
+					Metadata:       result.Metadata(c.line),
+					IdempotencyKey: fmt.Sprintf("earn:%s:%s", order.ID, c.currency),
+				},
+				Lots: []WalletLotInput{{
+					Amount:    c.line.Amount,
+					ExpiresAt: ComputeExpiry(ExpirySettings(orgSettings, c.currency), receivedAt),
+				}},
+			})
 			if err != nil {
 				return fmt.Errorf("crediting %s: %w", c.currency, err)
 			}