Migrate linting and formatting to Oxc

[smsunarto]

Summary

• replace the root Prettier workflow with Oxfmt while retaining 80-column formatting, existing ignores, and manifest key order
• migrate the app ESLint rules and Turbo inputs to Oxlint
• preserve the unsupported no-restricted-syntax policies through a focused local Oxlint plugin and update inline disable directives
• avoid a bulk formatting rewrite; the repository already has outstanding format differences

Why Oxlint + Oxfmt

The main payoff is materially faster feedback without broadening the change.

Before: 42.2 seconds with ESLint
After: 2.2 seconds with Oxlint, about a 19x improvement.

That shortens the edit-check loop locally and reduces time spent in the lint portion of CI.

The migration also simplifies the direct toolchain:

• Oxlint replaces ESLint, the TypeScript parser, and the React Hooks plugin.
• Oxfmt replaces Prettier. Supported TypeScript and React rules run natively, and lint plus format now come from the same Oxc ecosystem rather than separate JavaScript toolchains.

This repository is a good fit for the migration:

• the existing Node 22.19 minimum satisfies both tools
• Oxfmt targets Prettier 3.8 compatibility, which is the version being replaced
• explicit printWidth: 80 and sortPackageJson: false settings preserve current formatting intent and manifest order
• the existing lint paths, rule severities, ignore patterns, and Turbo caching boundaries remain intact
• no repository-wide reformat is included, keeping review noise low and blame history useful

The remaining compatibility gaps are bounded and visible. Oxlint does not implement no-restricted-syntax, so the three repository-specific AST policies live in a small local plugin and have been exercised against deliberate violations. The native React analyzer reports additional existing findings; preserve-manual-memoization remains warning-level so this tooling migration does not become unrelated application cleanup. Oxfmt is not byte-identical to Prettier, but with compatibility-focused settings it identifies only 30 additional files beyond the existing baseline.

Taken together, this gives the repository a substantially faster default workflow now, removes direct legacy lint and format dependencies, and keeps the migration reversible and reviewable rather than coupling it to thousands of formatting changes.

Verification

• pnpm exec turbo run lint --force
• pnpm exec turbo run typecheck --filter=@bb/app
• pnpm exec turbo run test --filter=@bb/templates --force
• pnpm exec oxfmt --check .oxfmtrc.json .oxlintrc.json package.json apps/app/package.json scripts/oxlint-plugin.mjs
• exercised all three local policy rules against deliberate violations

Formatting baseline

The previous Prettier check reported 459 existing files. Oxfmt reports 487 with compatibility-focused settings, including only 30 files not previously reported by Prettier. This PR intentionally does not reformat the repository.