skill: package elastic/agent-skills into dockyard

[JAORMX]

Package agent skills from elastic/agent-skills into the Dockyard registry.

Source

• Repo: https://github.com/elastic/agent-skills
• License: Apache-2.0
• Upstream HEAD (at survey time): 43f4c98 (2026-04-17)
• Skill count upstream: ~33
• Trust signal: Official Elastic; 364 stars

Candidate skills (examples; full curation at packaging time)

• cloud/access-management
• cloud/create-project
• cloud/network-security
• plus remaining skills in the repo

Acceptance criteria

• One spec.yaml per selected skill under skills/<name>/
• spec.ref pinned to an audited upstream commit SHA
• task validate-skill passes for each
• task scan-skill findings triaged
• Single PR grouping all Elastic skills (branch skills/elastic)

Part of the vendor-by-vendor sweep following #466 (Trail of Bits).