ci: check Go dependency licenses

[johnnygreco]

Summary

• inventory direct Go dependencies from go.mod and require go.sum for external modules
• resolve exact-version SPDX metadata through deps.dev, including versioned replacements
• validate affected modules with go mod tidy -diff and go mod verify
• document Go coverage and add focused regression tests

Validation

• dependency-license tests: 46 passed
• documentation tests: 23 passed, 3 skipped
• Dev Notes renderer: 11 passed
• full documentation build: passed with no issues
• native Go validation against PR 66: tidy diff clean; all modules verified

PR 66 result

The updated checker inventories 28 direct Go dependencies. Twenty-seven satisfy policy; github.com/NVIDIA/OpenShell/sdk/go has no public deps.dev license metadata and is correctly reported as unresolved. A separate exact-source clarification with authoritative evidence will be needed for that module.

[github-actions]

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