chore: Evaluate oxfmt as a prettier replacement

[antonis]

Summary

Evaluate replacing prettier with oxfmt (the Oxc formatter) for code formatting across the repository.

Motivation

• Recover import sorting — After migrating to oxlint (chore: Migrate from ESLint to oxlint #5867), we lost simple-import-sort/imports enforcement since oxlint has no equivalent rule. oxfmt supports import sorting natively, which would fill this gap.
• Align with Oxc toolchain — We already use oxlint for linting. Using oxfmt for formatting keeps the toolchain consistent (single ecosystem).
• Performance — oxfmt is significantly faster than prettier, same as oxlint vs ESLint.
• 100% prettier compatibility — oxfmt has 100% coverage of prettier for JavaScript/TypeScript, so migration should be low-risk.

Scope

1. Evaluate oxfmt's prettier compatibility for the codebase (run both, diff output)
2. Verify import sorting configuration meets our needs (single group, same order as simple-import-sort)
3. Test with CI pipeline
4. If viable: replace prettier with oxfmt in all workspaces, update lint/fix scripts

Considerations

• The repo also uses prettier for non-JS formatting — check if oxfmt handles all file types or if prettier needs to stay for some
• Sample apps and performance tests also use prettier
• sentry-javascript may also be evaluating this — coordinate if possible

Related

• chore: Migrate from ESLint to oxlint #5867 — Migrate from ESLint to oxlint
• RN-549 — Upgrade TypeScript from 4.9.5 to 5.x
• RN-479 — Investigate migrating from ESLint to oxlint

[linear-code]

RN-550