GitHub Actions CI/CD Pipeline

Create a GitHub Actions CI/CD pipeline for my project.

**Stack:** [YOUR_STACK — e.g., "Next.js, PostgreSQL, deployed to Vercel"]
**Package manager:** [npm / pnpm / yarn / bun]
**Test framework:** [vitest / jest / playwright]

Generate a `.github/workflows/ci.yml` that:

**On pull request:**
1. Install dependencies (with caching)
2. Run TypeScript type checking
3. Run ESLint
4. Run unit tests with coverage report
5. Run build to catch compile errors
6. Post a comment with test results summary

**On push to main:**
1. All of the above, plus:
2. Run E2E tests against a preview deployment
3. Deploy to production (if all checks pass)

Include:
- Dependency caching for faster runs
- Parallel jobs where possible
- Matrix testing if relevant (Node versions)
- Proper secret handling for environment variables
- Status badges markdown for README
- Estimated run time for each job

Use current best practices and latest action versions.