Stands up a lint, format, and pre-commit toolchain (Biome or ESLint flat config + Prettier, or ruff + ruff format) with .editorconfig, fast staged-only git hooks (husky+lint-staged or the pre-commit framework), and a check-only CI gate (lint --max-warnings=0 + format --check, no auto-fix), plus a one-shot reformat of a dirty repo hidden behind .git-blame-ignore-revs.
