Retrieve chronological analysis history for a domain with entity attribution diffs between runs.

External history: Set include_external=true to merge pre-WhoisGenius WHOIS ownership history into the timeline. External entries are labeled source: "external". This costs 50 credits per call.

Entity portfolio: GET /domains/{domain}/portfolio resolves the queried domain's top entity from its most recent analysis, then returns the other domains attributed to that same entity via Reverse WHOIS. The portfolio_count field reflects the total size of the entity's portfolio and may exceed the number of entries in domains, which is capped at 50. The domain must already have a completed analysis — submit it via POST /analyze first if you receive a 404.