refactor(test): parameterize pyproject SBOM tests and add doc comments

Extract shared SBOM_CASES constant and use forEach loops to eliminate
repetitive stack/component test pairs across uv, poetry, and pip suites.
Parameterize validateLockFile and workspace tests similarly. Add JSDoc
comments to all 39 test functions.

Implements TC-4065

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: ruromero