Add manage-authentication-policy skill

[jdanielmyers]

Summary

Adds the manage-authentication-policy skill — covers create, modify, view, attach, detach, drop, and recommend operations for Snowflake authentication policies. Spans AUTHENTICATION_METHODS (PASSWORD, SAML, OAUTH, KEYPAIR), MFA enforcement, PAT_POLICY, workload identity federation, CLIENT_TYPES, and minimum driver versions.

Promoted from snowflake-eng/cortex-code-skills/database-security/iam/authentication/manage-authentication-policy after audit review (top-7 strong-promote candidate from the 28-skill promotion candidate set). Fills a real security gap not currently covered by any bundled or Labs skill.

Files

• skills/manage-authentication-policy/SKILL.md — Labs frontmatter + main router
• skills/manage-authentication-policy/LICENSE — Snowflake Skills License (employee author)
• skills/manage-authentication-policy/references/property-reference.md — full property syntax / canonical sources
• skills/manage-authentication-policy/workflows/{create,modify,view,attach-detach,drop,recommend}.md — 6 sub-workflows

The internal skill_metadata/ directory (auditor seed file with owner email) was intentionally not promoted.

Audit pipeline status

audit run-tier labs --client mock:

• Blocking checks: 0 failures (frontmatter, license, no internal refs all pass)
• Advisory: 4 (word budget; no Overview/Common-Mistakes section; multi-language code blocks for Python+SQL)

Test plan

• Reviewer verifies frontmatter renders in skill catalog
• /skill add from this branch loads cleanly with all 6 workflow files and reference
• $manage-authentication-policy recommend authentication policies for my account based on recent login activity produces a useful recommendation
• Each workflow file is reachable from the main router