setup-pre-commitlisted

# Setup Pre-Commit Hooks ## Invocation Position This is an infrastructure skill, not a normal feature-delivery stage. Use `/setup-pre-commit` when a project needs commit-time formatting, linting, type checking, and test hooks. Do not use it as part of the default feature pipeline. It prepares the repo so later `/execute` and `/pre-merge` steps have stronger feedback loops. ## What This Sets Up - **Lefthook** for git hook management (fast, zero-dependency, config-as-code) - **Formatting + linting** on staged files (Biome preferred; Prettier, ESLint, or others supported) - **Typecheck** and **test** scripts in the pre-commit hook ## Steps ### 1. Detect Package Manager Check for `pnpm-lock.yaml` (pnpm), `package-lock.json` (npm), `yarn.lock` (yarn), `bun.lockb` (bun). Use whichever is present. Default to npm if unclear. Store the detected package manager — it's used for all install and run commands below. ### 2. Detect Existing Formatter/Linter Before installing anything, check what's already in the project: ```bash # Check package.json for existing tools cat package.json | grep -E "biome|prettier|eslint|oxlint|dprint" 2>/dev/null # Check for config files ls biome.json biome.jsonc .prettierrc .prettierrc.* prettier.config.* .eslintrc* eslint.config.* 2>/dev/null ``` **If an existing formatter/linter is detected:** use it. Don't install a competing tool. **If nothing is detected:** recommend Biome (single tool for formatting + linting, fast, zero-config defaults) a