feat: expose request IDs

[jbeckwith-oai]

Summary

• expose the server-generated x-request-id as _request_id on successful typed model and paginated responses
• expose request_id on API errors
• add RBI and RBS declarations plus user-facing documentation
• cover model responses, page responses, error responses, and serialization behavior

Why

The Ruby SDK retained response headers at the transport boundary but discarded them while coercing successful responses into typed objects. Errors retained their headers but required callers to inspect the header hash manually. This left Ruby behind the other official SDKs for request-ID convenience and made production troubleshooting harder.

Request IDs are response metadata, so they are attached only to the top-level returned object and are excluded from to_h, JSON, and YAML serialization.

Validation

• thermo-nuclear code-quality review
• ./scripts/test on Ruby 4.0.6 — 518 runs, 1702 assertions
• ./scripts/test on Ruby 3.3.12 — 518 runs, 1702 assertions
• bundle exec rake lint:rubocop — 2596 files, no offenses
• bundle exec rake typecheck:sorbet
• bundle exec rake validate:rbs — 1211 files
• bundle exec rake build:gem

Surface gap: https://openai-sdk-surface-atlas.openai.chatgpt.site/?capability=request-id#matrix

[openai-sdks]

OkTest Summary

✅ 237/237 SDK tests passed in 8.54s for Ruby SDK PR #352.

Test results — 42 files

Test	Result	Time
tests/chat-completions-complex-body.test.ts	✅ Passed	188ms
tests/chat-completions-create.test.ts	✅ Passed	260ms
tests/chat-completions-stream.test.ts	✅ Passed	128ms
tests/files-content-binary.test.ts	✅ Passed	285ms
tests/files-create-multipart.test.ts	✅ Passed	245ms
tests/files-list-pagination.test.ts	✅ Passed	180ms
tests/initialize-config.test.ts	✅ Passed	140ms
tests/instance-isolation.test.ts	✅ Passed	233ms
tests/models-list.test.ts	✅ Passed	175ms
tests/responses-background-lifecycle.test.ts	✅ Passed	223ms
tests/responses-body-method-errors.test.ts	✅ Passed	393ms
tests/responses-cancel-timeout.test.ts	✅ Passed	219ms
tests/responses-cancel.test.ts	✅ Passed	206ms
tests/responses-compact-retries.test.ts	✅ Passed	237ms
tests/responses-compact.test.ts	✅ Passed	211ms
tests/responses-create-advanced-stream.test.ts	✅ Passed	132ms
tests/responses-create-advanced.test.ts	✅ Passed	188ms
tests/responses-create-disconnect.test.ts	✅ Passed	148ms
tests/responses-create-errors.test.ts	✅ Passed	276ms
tests/responses-create-malformed-api-responses.test.ts	✅ Passed	151ms
tests/responses-create-retries.test.ts	✅ Passed	317ms
tests/responses-create-stream-failures.test.ts	✅ Passed	141ms
tests/responses-create-stream-timeout.test.ts	✅ Passed	212ms
tests/responses-create-stream-wire.test.ts	✅ Passed	1.945s
tests/responses-create-stream.test.ts	✅ Passed	132ms
tests/responses-create-terminal-states.test.ts	✅ Passed	258ms
tests/responses-create-timeout.test.ts	✅ Passed	222ms
tests/responses-create.test.ts	✅ Passed	305ms
tests/responses-delete.test.ts	✅ Passed	278ms
tests/responses-input-items-errors.test.ts	✅ Passed	195ms
tests/responses-input-items-list.test.ts	✅ Passed	208ms
tests/responses-input-items-options.test.ts	✅ Passed	216ms
tests/responses-input-tokens-count-timeout.test.ts	✅ Passed	328ms
tests/responses-input-tokens-count.test.ts	✅ Passed	245ms
tests/responses-malformed-inputs.test.ts	✅ Passed	2.091s
tests/responses-not-found-errors.test.ts	✅ Passed	300ms
tests/responses-parse.test.ts	✅ Passed	196ms
tests/responses-retrieve-retries.test.ts	✅ Passed	322ms
tests/responses-retrieve.test.ts	✅ Passed	232ms
tests/responses-stored-method-errors.test.ts	✅ Passed	660ms
tests/retry-behavior.test.ts	✅ Passed	1.875s
tests/sdk-error-shape.test.ts	✅ Passed	373ms

View OkTest run #31432280139

_{SDK merge (12016b4b9d39) · head (56fa2f2617e6) · base (20fbb0942991) · OkTest (91635c6a2723)}