refactor: Separate pure OpenAPI helpers from documentation I/O
Summary
Move reference resolution, schema examples and curl generation into pure focused modules; leave filesystem access and caching in docs-server. API source/generated contracts unchanged.
Verification
168 tests in 49 files, typecheck, lint and production build pass (538 pages). Independent reviewer verified the original extraction and repeated 32 migration/playground tests. A subsequent auth-rendering correction is documented below.
Scope and review
Part of the user-requested Recoup monorepo untangle-codebase workflow. Audit and decision log preceded implementation. Changes stay in this owning repository; no production deployment or main-branch merge requested. No broad comment/test-pruning sweep. Existing local work and retired checkouts preserved.
Each repository PR is independently reviewable; the Mono report will collect the coordinated audit, retained cases and check limitations.
Review follow-up
The curl renderer now emits every scheme in the selected first OpenAPI security requirement (AND), preserving first-alternative selection (OR), and places API keys in their declared header/query/cookie location. The actual guest claim needs both GuestSession cookie and BearerAuth; guest read needs its cookie. Five focused regressions failed before fixing. Added reference/example behavior cases bring the suite to 168 tests in 49 files; typecheck, lint and build (538 pages) pass. No endpoint authentication or API schema source changed.