feat: Add pre-commit hooks with Husky

Description

Set up Husky and lint-staged for automatic code quality checks before commits.

Problem

• README mentions "Husky for pre-commit hooks" but no .husky/ directory exists
• No automated checks before committing
• Code style issues can be committed
• Tests not run before push
• Potential for broken commits to reach CI/CD

Current State

• Prettier is configured (.prettierrc)
• ESLint is configured (eslint.config.mjs)
• No pre-commit automation

Proposed Solution

Install Husky with these hooks:

Pre-commit:

• Run Prettier on staged files
• Run ESLint on staged files
• Run TypeScript type checking

Pre-push:

• Run test suite (pnpm test)
• Ensure no console.log statements (optional)

Acceptance Criteria

• Install Husky and lint-staged
• Configure pre-commit hook
• Configure pre-push hook
• Run Prettier on staged files
• Run ESLint on staged files
• Run TypeScript checks
• Run tests before push
• Update README with hook documentation
• Add setup script in package.json
• Test hooks work for new contributors

Implementation

// package.json
{
  "scripts": {
    "prepare": "husky install"
  },
  "lint-staged": {
    "*.{ts,tsx}": [
      "prettier --write",
      "eslint --fix"
    ],
    "*.{json,md}": [
      "prettier --write"
    ]
  }
}

Files to Create/Modify

• package.json - Add dependencies and scripts
• .husky/pre-commit - Pre-commit hook
• .husky/pre-push - Pre-push hook
• README.md - Update hook documentation