explicit CI/CD configuration

Always use explicit configuration in CI/CD workflows rather than relying on defaults or convenience shortcuts. This includes pinning exact tool versions, specifying action parameters explicitly, and choosing reliable installation methods.

Key practices:

• Pin exact versions across all environments (e.g., version: v1.64.7 instead of version: v1.64)
• Use go install for Go tools instead of third-party GitHub actions that may become unmaintained
• Explicitly set action parameters even when overriding defaults (e.g., cache: false for setup-go)

Example of explicit configuration:

- name: Install Go
  uses: actions/setup-go@v4
  with:
    go-version: 1.21.0  # exact version
    cache: false        # explicit cache setting

- name: Install gotestsum
  run: go install gotest.tools/gotestsum@v1.11.0  # exact version via go install

This approach ensures reproducible builds, reduces dependency on external maintainers, and makes workflow behavior predictable across different environments and over time.