ARC0012: Built-in error thrown from an artifact

What

A decorated command, validator, or read model throws new Error (or another built-in error). Rule: arc-core/arc0012.

Why

A domain-named error identifies the failure in logs and direct calls. This checks throw new ..., not indirect calls or imported aliases.

Bad

@command()
export class Register { handle() { throw new Error('Already registered'); } }

Good

@command()
export class Register { handle() { throw new AlreadyRegistered(); } }