Regenerate twins after the trax machine generate defaults changed

Applies from: Trax 1.63.1.

The defaults of trax machine generate changed when the engine began shipping inside the tool and on npm as @traxsharp/state-machine:

Without --engine-src the twin now imports the installed package (--import-style specifier). Earlier versions required --engine-src and imported the engine by relative path. With --engine-src the default is still relative.
The default specifier is @traxsharp/state-machine. It used to be state-machine in the @trax scope, which Trax does not own on npm. If you vendor the engine behind another name or path alias, pass it with --specifier <module>.
A specifier twin's header now names the import it was generated with, and its IR records the IR format. Both are new lines in the generated file, so the first regeneration after upgrading shows them as a diff.

Regenerate with the new defaults

Install @traxsharp/state-machine in the frontend that imports the twin.
Run trax machine generate without --engine-src, and commit the regenerated twin, IR and corpus.
Run trax machine check in CI as before; it fails on a twin left from the previous tool.

Keep generating as before

Pass --import-style relative --engine-src <engine/src> for a relative twin, or --import-style specifier --specifier <module> for one importing your own name for the engine.

Why the twin records the IR format, and what the installed package checks on load, is in The codegen pipeline.