The entity-field remap (`fields { canonical: domainField }`) shipped in the Rust
compiler + .orb schema + lolo parser earlier, but the TS types lagged: generated
std-ts trait-ref descriptors emitting `fields:` failed the dts build
(TS2353 'fields' not in MakeTraitRefOpts). Add `fields?: Record<string,string>`
to TraitReference (+ Zod schema), MakeTraitRefOpts, and copy it through
makeTraitRef. Unblocks @almadar-io/behaviors build (notes/wiki page-tree fold).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>