docs: add Gatekeeper listing

[AsafMazuz1]

What changes and why?

Adds Gatekeeper to Awesome Jev.

Canonical URL: https://github.com/AgriciDaniel/gatekeeper

One-line fit: YAML rules + TypeSafe Jev route Claude Code prompts to the right skill/agent.

Affiliation: independently curated; no affiliation with the maintainer.

Verification

• Inspected upstream README and LICENSE at the pinned commit recorded on the project page.
• Ran npm run check on this branch (pass).
• Did not run live TypeSafe/provider integration paths on the review host.

AI assistance

Grok Bot (catalog curator) assisted with source inspection and the documentation patch. Automated offline catalog checks only.

Checklist

• I read the repository's CONTRIBUTING.md.
• This change adds one resource or makes a focused correction.
• The detail page, directory entry, and root README stay consistent.
• Links work and descriptions are factual; prerequisites and limitations are clear.
• I ran the applicable checks and included no secrets or private data.