feat(api): fix POST /invoice

internal/api/httpinvoce/routes.go

@@ -4,6 +4,8 @@ import (
 	"net/http"
 )
 
+// RegisterRoutes registers the HTTP routes for the invoice service.
 func (s Service) RegisterRoutes(mux *http.ServeMux) {
 	mux.HandleFunc("POST /invoice", s.createInvoice)
+	mux.HandleFunc("POST /invoice/send", s.sendInvoice)
 }