ADR-Lite: Use Biome as the toolchain
Status: Accepted (2026-04-21)
Decision
We will use Biome 1.9 (not Prettier + ESLint) as the linter and formatter across all packages in the monorepo.
Why
Single-binary install + single config file removes one onboarding step and one pre-commit failure mode. The marginal capability gap to the ESLint plugin ecosystem hasn't bitten us in 6 months of evaluation against the existing codebase.
Consequences
We give up some niche ESLint plugins — no React Compiler lint, no Storybook-specific rules — until Biome closes those gaps. We're betting that happens before we feel the absence.