List Country Codes

Returns the ISO 3166-1 alpha-3 country codes accepted by the Agent Primitive search endpoints. Ordered by company volume so the highest-coverage codes (USA, GBR, CHN, FRA, IND, DEU, ...) come first.

Where these codes are used:

• GET /api/v2/tech/companies - hq_country_code parameter.

One-shot discovery call - static, safe to cache.