Covers Pattern A (API consumer, any language, start today) and Pattern B
(IHP extension hub, Haskell, shares haskelseed build infra). Includes honest
Haskell/IHP assessment, build-time estimates, hub-core sketch, and a
concrete checklist. References existing domain-hub-extension-guide.md for
type vocabulary registration.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
