release: 2.51.0 (#3553)

Automated Release PR
---


## 2.51.0 (2026-07-30)

Full Changelog:
[v2.50.0...v2.51.0](https://github.com/openai/openai-python/compare/v2.50.0...v2.51.0)

### Features

* **api:** fast tier
([8808ed2](https://github.com/openai/openai-python/commit/8808ed27952dae13fb8761f045376af5b3e5bec2))


### Bug Fixes

* **api:** add fast tier to helper methods
([6064126](https://github.com/openai/openai-python/commit/60641266ff4b296044a81fe1717c17a70ceadbf1))

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Co-authored-by: stainless-app[bot] <142633134+stainless-app[bot]@users.noreply.github.com>
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