[containarium-ci]

Proposed by the coding agent on a member's box for #18 (run 5605d250).

Review this like any other change. The agent ran on the member's own machine from the text of the issue; the platform has not built or tested it.

• Tests, as reported by the agent: not_run
• Files: 2

The platform made the commit and the branch for this pull request from the files the agent handed back at the end of its run; it does not use the agent's own git state on the box. Anything the summary below says about committing, branching or pushing describes only what the agent itself could do on the box.

The agent's summary, quoted:

Added docs/glossary.md with one short entry for each term the issue lists, and one line in README.md linking to it. The High/Medium/Low confidence levels match the README table, with the PRD's one-line meanings added. 'Passive only' is taken from the README and PRD. SBOM, VEX, KEV, EPSS, OSV, CSAF and backport are not defined in the README or PRD, so each entry says so and records only how the PRD uses the term. The glossary says nothing is implemented yet, matching the README. Tests were not run: the change is docs only, and the Go and Node tools are not installed on this box. Committed on branch agent/issue-18; nothing was pushed.