Function row_change_to_json 

pub fn row_change_to_json(table: &str, change: &SourceChange) -> Value

One row change in the change-source ingest shape — the changes[] element rindled’s /apply-row-change-txn consumes (rindle-replica’s mutation_from_json is the decode dual): add → {row}, remove → {old}, edit → {old, row} where row is the NEW image. Deliberately distinct from normalized_op_to_json — that is the OUTBOUND batch wire, where remove carries row and edit carries new. The room’s write-behind flush emits this shape (RINDLE-REALTIME-DESIGN.md §5.3), with old carrying the base image the CAS precondition asserts. NOTE: this emitter renders cells via owned_to_json, which is FLOAT-FORM for Int — it is NOT the integer-exact ingest codec (rindle-replica::wire_json::mutation_to_json, design 226 Stage D). Room cells are Number-plane today so nothing is lost; unify onto the exact codec before any exact-int producer feeds this path.