fix(openai): omit temperature for o1/o1-mini/o1-preview reasoning models

[zjshen14]

Summary

• The o1/o1-mini/o1-preview family of OpenAI reasoning models does not accept a temperature parameter (it is fixed at 1 server-side). Passing temperature to these models causes a 400 Invalid parameter API error.
• Added a lacksTemperatureSupport() helper that matches the o1 family specifically; o3 and o4 variants do support temperature and are unaffected.
• The bug is triggered today when a user runs opencli run "..." --model o1-mini --temperature 0.5.

Related issue

Part of #43

Test plan

• npm run typecheck && npm run lint && npm run format:check && npm test — all pass (699 tests)
• New tests verify temperature is omitted for o1, o1-mini, o1-preview
• New tests verify temperature IS passed for gpt-4o and o3-mini
• Existing test for developer role on o-series models still passes

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[zjshen14]

Review: fix(openai): omit temperature for o1/o1-mini/o1-preview reasoning models

What's good: Correct fix, correct regex (^o1(-|$) — matches o1, o1-mini, o1-preview, and nothing else). The tests are comprehensive: gpt-4o and o3-mini still receive temperature, o1/o1-mini/o1-preview don't, and the no-temperature-configured case is also covered. CI is green.

One minor style note: several new test cases re-mock OpenAI at the top of the test body via vi.mocked(OpenAI).mockImplementation(...) even though the same mock is already set by the outer beforeEach. The re-mocks in the o3-mini, o1, o1-mini, and o1-preview cases are no-ops. Not a correctness issue, just noise — the gpt-4o test doesn't need the re-mock and neither do these.

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I'm not merging this directly because src/providers/openai.ts falls under src/providers/*, which the review-bot policy reserves for human sign-off even for well-contained fixes. The code is solid and the restriction is positional, not substantive.

Recommendation: Merge — the change is correct and the tests are thorough.

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