syntax = "proto3";
package handbook.v1;
message ProjectionFact {
  string event_id = 1;
  string tenant_id = 2;
  string currency = 3;
  int64 amount_minor = 4;
  string occurred_at = 5;
  int64 entity_version = 6;
  int32 schema_version = 7;
  reserved 8, 9;
  reserved "legacy_balance";
}
// Contract illustration; compilation/Registry compatibility not implied.