Add a domain-discovery step to the enrichment pipeline so the catalog's
domain set, previously written only by the curated seed, grows
automatically. A focused agent enumerates the registrable domains a
vendor owns and operates - marketing, product and sub-brand, app, API,
and CDN/asset domains - from links seen while browsing and from web
search, anchored on the website resolved earlier in the run.
A deterministic ownership gate reduces the candidates to eTLD+1 and
keeps only those that clear a strict confidence floor and match the
vendor by domain label. Shared tracker-delivery and CDN infrastructure
is dropped unless the vendor itself is that provider, in which case its
own brand-matching domain passes a stricter exact-label check. The
survivors are upserted into common_third_party_domains in the run's
final transaction and recorded in the enrichment payload, feeding the
tracker-mapping domain step and disambiguation.
Signed-off-by: Émile Ré <emile@probo.com>