Complete CI/CD Pipeline with GitHub Actions for Next.js Applications

Create a complete CI/CD pipeline with GitHub Actions for [PROJECT NAME], a Next.js [VERSION] application deployed on [VERCEL/AWS/DOCKER + VPS].

**Context:**
- Repository: monorepo [YES/NO]
- Branches: main (production), develop (staging), feature/*
- Existing tests: [NUMBER] unit, [NUMBER] E2E
- Database: [POSTGRESQL/MYSQL] — migrations required
- Environment variables: [NUMBER] secrets

**Workflow 1 — Pull Request (CI):**
```yaml
# Trigger: push to any branch except main
```
- Checkout + node_modules cache (pnpm store)
- Type checking: `tsc --noEmit`
- Linting: ESLint + Prettier check
- Unit tests: Jest/Vitest with coverage report
- E2E tests: Playwright with failure screenshots
- Verification build: `next build`
- Automatic preview deployment (unique URL per PR)
- Automatic PR comment with: preview link, coverage %, bundle size diff
- Mandatory status checks for merge

**Workflow 2 — Merge to main (CD):**
```yaml
# Trigger: push to main
```
- All CI checks
- Database migrations (with automatic rollback on failure)
- Optimized production build
- Deploy to [ENVIRONMENT]
- Post-deploy smoke tests (health check + critical endpoints)
- Slack/Discord notification: success or failure
- Automatic semantic versioning tag

**Workflow 3 — Scheduled (Maintenance):**
- Dependabot/Renovate: dependency updates
- Weekly security audit (`pnpm audit`)
- Lighthouse CI: performance monitoring
- Database backup verification

**Advanced Configuration:**
- Matrix strategy for testing on Node 18 and 20
- Concurrency: cancel previous workflows on the same branch
- Docker layer caching (if applicable)
- Secrets management: GitHub Environments (staging, production)
- Recommended branch protection rules

Provide complete, functional YAML files for each workflow.