Implement CI/CD pipeline for the monorepo

[yashdev9274]

Description

Set up GitHub Actions workflows for automated testing, linting, typechecking, and deployment.

Expected Deliverables

• Create .github/workflows directory with:
  • CI workflow: lint, typecheck, build on PR/push
  • Deploy workflow: deploy web app on merge to main
• Add badges to README.md

Areas to Consider

• Caching node_modules and build artifacts
• Matrix strategy for testing across Node versions
• Separate jobs for different apps/packages