Module mutation 

Mutation: checked edits to entities already in the model.

Internal split

• edit.rs: schema-agnostic edit operations (set_attribute, retype, remove) — the mutable counterpart to insert/push.
• transaction.rs: preflight and atomic commit.
• conflict.rs: ID/reference/index conflict diagnostics.

edit.rs adds inherent Model methods; transaction.rs owns the batched authoring contract. Both are re-exported at the crate root.

Structs

Applied

What a committed transaction did.

Transaction

A batch of edits, validated together and applied as a unit.

Enums

Conflict

A reason a transaction cannot be committed.

Edit

One staged change.