chore: react@next CI checks

[mdjastrzebski]

Summary

Adds a release guard that fails once npm react@latest moves past the supported stable window defined in testRenderer.supportedReactRange, and updates automation to exercise that policy in nightly CI. It also adds the event-related host config hooks newer react-reconciler builds expect at runtime, updates ESLint handling for .mjs scripts, renames formatting scripts to format / format:fix, and covers the release guard with a dedicated Jest test.

Type of change

• Bug fix
• New feature
• Breaking change
• Documentation update
• Other (specify below)

Other: CI and release guard maintenance for React compatibility support.

How Has This Been Tested?

• bun run typecheck
• bun x jest --watchman=false
• bun run format

Checklist:

• Code follows style guidelines
• Self-review completed
• Code commented where necessary
• Documentation updated
• No new warnings generated
• Tests added/updated and passing
• Code coverage maintained/improved
• Dependent changes merged

Additional Notes:

• peerDependencies.react remains broad as ^19.0.0, while testRenderer.supportedReactRange explicitly records the tested stable support window as >=19.0.0 <19.3.0.
• Formatting scripts are renamed to format / format:fix while still using Prettier under the hood.
• PR CI now validates against 19.0.0 and ~19.0.0, while nightly adds the React release guard and still keeps a dedicated React canary job.
• The release guard derives the supported React ceiling from testRenderer.supportedReactRange, checks npm metadata, and fails with an actionable message once the latest stable React release moves outside that configured window.
• eslint.config.js now disables typed lint rules for js/mjs/cjs files so the new release-guard script can live outside the TypeScript project graph.
• GitHub Actions were updated to actions/checkout@v5 and codecov-action@v5, and the workflows set FORCE_JAVASCRIPT_ACTIONS_TO_NODE24=true.
• The host config now defines trackSchedulerEvent, resolveEventType, and resolveEventTimeStamp so newer reconciler builds do not crash on missing runtime hooks even when @types/react-reconciler lags behind.