Keep legacy subscription tables as unmanaged instead of dropping them

prisma/schema.prisma

@@ -130,6 +130,9 @@ model Proclamation {
   groupId              Int
   group                ProclamationGroup    @relation(fields: [groupId], references: [id])
   userProclamations    UserProclamations[]
+  // Legacy subscription-level FK. Retained in the database but unmanaged; the
+  // FK constraint is dropped and the value is left NULL. Hidden from the client.
+  subscriptionLevelId  Int?                 @ignore
 }
 
 model ProclamationGroup {
@@ -198,6 +201,9 @@ model LicenseKey {
   userId String?
   user   User?   @relation(fields: [userId], references: [id], onDelete: SetNull)
   email  String?
+  // Legacy subscription level. Retained in the database but unmanaged; hidden
+  // from the client and left NULL.
+  level  String? @ignore
 
   @@index([userId])
   @@index([email])