Add OneRoster REST API documentation

[ottenhoff]

What changed

• add a workflow-first OneRoster 1.2 REST guide
• generate an 81-operation catalog from the OpenAPI-derived registry
• check generated documentation for drift during pnpm run check
• include the documentation in the npm package

Why

Callers need a quick path from common integration tasks to the correct typed client method, raw HTTP endpoint, query controls, success status, and OAuth scopes. The generated catalog keeps that reference aligned with the operation registry without requiring network access during normal checks.

Validation

• pnpm run check
• 41 test files and 317 tests passed
• pnpm run build
• pnpm pack --dry-run

[ottenhoff]

Closing this draft because the requested changes were pushed directly to main.