This change adds `//go:build integration` to all files in integration_tests/ so they are excluded from `go test ./...` by default. Run them explicitly with `go test -tags integration` or `make integration-tests`. This simplifies the Makefile test target — no more shell pipeline to filter out the integration_tests package. While in here, I've also made it so that the test targets use `gotestsum` to give much, much nicer output while running tests. Testing Done: - Ran unit tests. - Ran integration tests.