This commit introduces a `Makefile` to standardize the build, test, and linting process, as suggested in the `TODO.md` file.
The `Makefile` includes targets for `lint`, `test`, and `test-integration`.
The `.github/workflows/ci.yml` file has been updated to use the `make test-integration` target, simplifying the CI configuration.
The `.github/workflows/cd.yml` file has been updated to be ready for deployment to a staging environment. It now calls a `make deploy-staging` target, which serves as a placeholder for the actual deployment script.
This work addresses the 'Establish a CI/CD Pipeline' task from the `TODO.md`.
