Add configurable LNbits invoice memos and pubkey metadata

Read INVOICE_MEMO_YEARLY and INVOICE_MEMO_LIFETIME from the environment
and pass the user pubkey in LNbits payment extra for invoice creation.

internal/invoice/service.go

@@ -20,6 +20,8 @@ type Pricing struct {
 	YearlySats   int64
 	LifetimeSats int64
 	ExpiryMins   int
+	MemoYearly   string
+	MemoLifetime string
 }
 
 type Service struct {
@@ -131,17 +133,15 @@ func (s *Service) Create(ctx context.Context, req CreateRequest) (*PendingInvoic
 	}
 
 	amount := s.pricing.YearlySats * int64(req.Years)
+	memo := s.pricing.MemoYearly
 	if req.SubscriptionType == user.SubLifetime {
 		amount = s.pricing.LifetimeSats
-	}
-
-	memo := fmt.Sprintf("%s@%s", username, s.domain)
-	if isRenewal {
-		memo = "renewal: " + memo
+		memo = s.pricing.MemoLifetime
 	}
 
 	expirySecs := s.pricing.ExpiryMins * 60
-	hash, request, err := s.lnbits.Create(ctx, amount, memo, expirySecs)
+	extra := map[string]string{"pubkey": req.Pubkey}
+	hash, request, err := s.lnbits.Create(ctx, amount, memo, expirySecs, extra)
 	if err != nil {
 		return nil, err
 	}