lnd: validate native-sql network on startup

Author: ziggie1984

config_builder.go

@@ -1235,6 +1235,22 @@ func (d *DefaultDatabaseBuilder) BuildDatabase(
 			return nil, nil, err
 		}
 
+		// Validate that the database was initialised for the same
+		// network as the currently active network. This catches the
+		// case where a user accidentally reuses a postgres DSN across
+		// different networks (e.g. mainnet → testnet), which would
+		// otherwise lead to silent data corruption. For file-based
+		// backends (SQLite) this is a no-op because filesystem paths
+		// already enforce network separation.
+		network := lncfg.NormalizeNetwork(cfg.ActiveNetParams.Name)
+		err = dbs.NativeSQLStore.ValidateNetwork(ctx, network)
+		if err != nil {
+			cleanUp()
+			d.logger.Error(err)
+
+			return nil, nil, err
+		}
+
 		// With the DB ready and migrations applied, we can now create
 		// the base DB and transaction executor for the native SQL
 		// invoice store.