openai-codex models have wrong contextWindow (272K instead of 400K)

[sauerdaniel]

All 6 openai-codex models in packages/ai/src/models.generated.ts have contextWindow: 272000. OpenAI's platform docs list them all at 400,000.

Models affected: gpt-5.1, gpt-5.1-codex-max, gpt-5.1-codex-mini, gpt-5.2, gpt-5.2-codex, gpt-5.3-codex.

Sources:

• https://platform.openai.com/docs/models/gpt-5.1 — 400,000 context window
• https://platform.openai.com/docs/models/gpt-5.1-codex — 400,000 context window
• https://platform.openai.com/docs/models/gpt-5.1-codex-mini — 400,000 context window
• https://platform.openai.com/docs/models/gpt-5.2 — 400,000 context window
• https://platform.openai.com/docs/models/gpt-5.2-codex — 400,000 context window
• https://platform.openai.com/docs/models/gpt-5.3-codex — 400,000 context window

I have a fix ready at #1461 — one-line change per model. Happy to resubmit the PR once approved.