fix(zod): support only provably JSON-native structured outputs

[HAYDEN-OAI]

Supersedes #2376 with an intentionally smaller, fail-closed contract. The previous PR accumulated 8,554 added lines while trying to infer the behavior of arbitrary Zod transformations; this replacement does not modify the vendored converter.

• Document and enforce the Zod v3 JSON-native subset at the shared strict-helper boundary.
• Reject native Date/BigInt/Map/Set/Promise values, effects/refinements, pipelines, intersections, invalid defaults, and ambiguous unions with actionable errors.
• Preserve disjoint/discriminated unions, recursive/shared schemas, non-strict Realtime behavior, and the existing Zod v4 converter.
• Represent precision-sensitive integers as validated decimal strings and convert with BigInt only after parsing.
• Reconcile the few existing fixtures that explicitly depended on unsupported behavior.

Verification: 65 regression-first failures became 83 passing boundary tests; 456 focused Zod/parser tests, 3,372 handwritten tests, 559 generated tests, full formatting/lint, repository types, CommonJS/ESM production build, published TypeScript 4.9/current consumers, and the packed npm artifact all pass.

Additional schema capabilities should be considered as separate, narrowly scoped follow-ups rather than expanding this boundary into a general transformation interpreter.

[openai-sdks]

OkTest Summary

✅ 237/237 SDK tests passed in 11.405s for Node SDK PR #2396.

Test results — 42 files

Test	Result	Time
tests/chat-completions-complex-body.test.ts	✅ Passed	208ms
tests/chat-completions-create.test.ts	✅ Passed	298ms
tests/chat-completions-stream.test.ts	✅ Passed	254ms
tests/files-content-binary.test.ts	✅ Passed	216ms
tests/files-create-multipart.test.ts	✅ Passed	210ms
tests/files-list-pagination.test.ts	✅ Passed	199ms
tests/initialize-config.test.ts	✅ Passed	204ms
tests/instance-isolation.test.ts	✅ Passed	145ms
tests/models-list.test.ts	✅ Passed	178ms
tests/responses-background-lifecycle.test.ts	✅ Passed	216ms
tests/responses-body-method-errors.test.ts	✅ Passed	411ms
tests/responses-cancel-timeout.test.ts	✅ Passed	239ms
tests/responses-cancel.test.ts	✅ Passed	276ms
tests/responses-compact-retries.test.ts	✅ Passed	275ms
tests/responses-compact.test.ts	✅ Passed	322ms
tests/responses-create-advanced-stream.test.ts	✅ Passed	175ms
tests/responses-create-advanced.test.ts	✅ Passed	209ms
tests/responses-create-disconnect.test.ts	✅ Passed	1.097s
tests/responses-create-errors.test.ts	✅ Passed	263ms
tests/responses-create-malformed-api-responses.test.ts	✅ Passed	199ms
tests/responses-create-retries.test.ts	✅ Passed	299ms
tests/responses-create-stream-failures.test.ts	✅ Passed	232ms
tests/responses-create-stream-timeout.test.ts	✅ Passed	2.156s
tests/responses-create-stream-wire.test.ts	✅ Passed	2.429s
tests/responses-create-stream.test.ts	✅ Passed	135ms
tests/responses-create-terminal-states.test.ts	✅ Passed	367ms
tests/responses-create-timeout.test.ts	✅ Passed	282ms
tests/responses-create.test.ts	✅ Passed	305ms
tests/responses-delete.test.ts	✅ Passed	227ms
tests/responses-input-items-errors.test.ts	✅ Passed	348ms
tests/responses-input-items-list.test.ts	✅ Passed	165ms
tests/responses-input-items-options.test.ts	✅ Passed	196ms
tests/responses-input-tokens-count-timeout.test.ts	✅ Passed	248ms
tests/responses-input-tokens-count.test.ts	✅ Passed	291ms
tests/responses-malformed-inputs.test.ts	✅ Passed	2.065s
tests/responses-not-found-errors.test.ts	✅ Passed	342ms
tests/responses-parse.test.ts	✅ Passed	179ms
tests/responses-retrieve-retries.test.ts	✅ Passed	310ms
tests/responses-retrieve.test.ts	✅ Passed	237ms
tests/responses-stored-method-errors.test.ts	✅ Passed	797ms
tests/retry-behavior.test.ts	✅ Passed	3.112s
tests/sdk-error-shape.test.ts	✅ Passed	365ms

View OkTest run #32174812497

_{SDK merge (da4113677c54) · head (6037a8a6f7bc) · base (dd945e63d9c3) · OkTest (7e7850017529)}

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 71780bf0c5

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 6cbcdbb468

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 7c292d83a8

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: d5f565293f

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".