perf(react-compiler): enable controlled state and outside-click hooks

[joshblack]

Follow up to #8555. Enable React Compiler for useControllableState, useOnOutsideClick, and our internal development-only effect hook.

Keep the hooks that need broader dependency or focus-lifecycle changes excluded.

Changelog

New

Changed

• Capture the initial controlled/uncontrolled mode in state instead of reading a ref during render. The mode remains fixed for the hook's lifetime.
• Allocate outside-click handler IDs through lazy state initialization, preserving numeric priority for nested handlers.
• Select the development-only effect implementation at module initialization: React's effect hook in development and a no-op in production.
• Remove the three compiler exclusions and add a minor changeset, matching our recent compiler rollout.

Removed

Rollout strategy

• No changes needed in github/github-ui
• Needs changes in github/github-ui
• Ships with feature flag(s)
• Not sure
• None

[changeset-bot]

🦋 Changeset detected

Latest commit: 8717c36

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@primer/react	Minor

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[github-actions]

⚠️ Action required

👋 Hi, this pull request contains changes to the source code that github/github-ui depends on. If you are GitHub staff, test these changes with github/github-ui using the integration workflow. Check the integration testing docs for step-by-step instructions. Or, apply the integration-tests: skipped manually label to skip these checks.

[primer-integration]

Integration test results from github/github-ui PR:

  Changes Waiting
  CI Passed
  VRT Passed
  Projects Passed

[Copilot]

🟢 Approval recommended

The focused refactors preserve existing behavior and include targeted regression coverage; no blocking issues were identified, though tests were not executed.

0 open findings

What changed in this PR

Continues the React Compiler rollout from #8555 by enabling compilation for three hooks while preserving their existing behavior.

Changes:

• Replace render-time ref access and memoized handler IDs with state initialization.
• Select the development-only effect implementation at module initialization.
• Remove compiler exclusions, add regression tests, and include a minor changeset.

File	Description
packages/​react/​src/​internal/​hooks/​useDevOnlyEffect.ts	Selects the effect implementation at module initialization.
packages/​react/​src/​hooks/​useOnOutsideClick.tsx	Allocates stable handler IDs through lazy state.
packages/​react/​src/​hooks/​useControllableState.ts	Stores the initial controlled mode in state.
packages/​react/​src/​hooks/​__tests__/​useOnOutsideClick.test.tsx	Tests nested priority, cancellation, and cleanup in StrictMode.
packages/​react/​src/​hooks/​__tests__/​useControllableState.test.tsx	Tests setter stability and callback freshness.
packages/​react/​script/​react-compiler.mjs	Removes the three hook exclusions.
.changeset/​react-compiler-hooks.md	Records compiler support as a minor release.

🧠 Review effort: Balanced

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