chore: migrate from ESLint to Biome for linting (#3694)
Replace ESLint with Biome for ~14x faster linting (~360ms vs ~5s).
- Add biome.json with rules matching ESLint parity (Next.js, a11y,
TypeScript, unused vars/imports)
- Remove eslint, @typescript-eslint/*, eslint-config-next,
eslint-plugin-jsx-a11y, @eslint/* from deps
- Remove eslint.config.mjs
- Update lint script to: tsgo --noEmit && biome check .
- Fix 11 real code issues caught by Biome (banned types, explicit any,
unsafe finally, unreachable code, shadowed names)
- Disable Biome formatter (Prettier stays for Tailwind class sorting)
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Huang Xin
956c71cd7b