fix(linter): Move typescript/prefer-optional-chain to nursery for now.

[connorshea]

The rule is quite complex, so we want to make sure we get it right before we move it to wider usage. You can still use it, but it may have some edge-cases where it behaves incorrectly still.

e.g. #18110, #17968, #18106

[Copilot]

Pull request overview

This PR moves the typescript/prefer-optional-chain linter rule from the "style" category to the "nursery" category to allow for further refinement and edge-case testing before promoting it to wider usage.

Changes:

• Added documentation explaining the rule's nursery status and the complexity of the autofix logic
• Changed the rule category from "style" to "nursery" with an explanatory comment

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[codspeed-hq]

Merging this PR will not alter performance

✅ 4 untouched benchmarks
⏩ 41 skipped benchmarks¹

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_{Comparing babysit (303bab3) with main (85a846c)}

Footnotes

1. 41 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[connorshea]

Merge activity

• Jan 19, 1:07 AM UTC: The merge label '0-merge' was detected. This PR will be added to the Graphite merge queue once it meets the requirements.
• Jan 19, 1:08 AM UTC: connorshea added this pull request to the Graphite merge queue.
• Jan 19, 1:13 AM UTC: Merged by the Graphite merge queue.