- TextDoc carries gator keyword fields (doc_sha, number, seller, total, typ,
issued_at, created_at, status, url); content is now omitempty so a partial
doc can be written.
- oo_docs_text mapping extended with the keyword fields.
- ESTextIndex.UpsertFields: bulk update + doc_as_upsert, merging gator fields
into an existing text doc without clobbering title/content.
- SearchQuery gains Seller/Number/Status term filters; SearchHit.Fields exposes
the gator values. Pure builders unit-tested.