Add stata-mcp fixed release reference

[cookesan]

Adds stata-mcp fixed release reference to GHSA-4p62-hqp5-g644.

Audit refresh, July 8, 2026:

• Confirmed the live PR is open, ready for review, merge-clean, and the visible advisory check is green.
• Rechecked the merge-base diff: exactly one advisory JSON file changes (advisories/github-reviewed/2026/06/GHSA-4p62-hqp5-g644/GHSA-4p62-hqp5-g644.json), JSON parses, git diff --check passes, and the exact-head worktree is clean.
• Revalidated the added public references and package-version evidence in the diff; all resolve through their source site or registry.

[cookesan]

Rechecked this reference-only PR while keeping the open Advisory Database queue current.

• The patch only adds the MCP-for-Stata fixed release reference; it does not change affected ranges, package metadata, or severity.
• The release tag resolves as v1.17.3.
• The release name is V1.17.3.

No other advisory fields are changed.