qunatity ledger in table definition

common/proto/table_structure.proto

@@ -73,9 +73,8 @@ message TableColumn {
   // Typically true for the "id" column created by the system.
   bool is_primary_key = 4;
 
-  // True for a user-defined column whose logic should be recomputed whenever
-  // one of its dependencies changes. False for system and foreign-key columns.
-  reserved 5;
+  // True when this column is projected from the profile quantity ledger.
+  bool quantity_ledger = 5;
 
   // True when the server created this as a companion of another logical column.
   bool generated = 6;