Fix formatting of description in SKILL.md

[cloudbypriyank]

Summary

Fixes the invalid YAML frontmatter in
agent_scan/prompt/skills/agentic-supply-chain-detection/SKILL.md.

The description field contained an unquoted colon, causing YAML
parsing to fail.

Changes

• Quote the description value in the YAML frontmatter.
• No other behavior or skill content was changed.

Related Issue

Closes #577

[boy-hack]

Thanks @cloudbypriyank for the fix! Quoting the description value is the correct fix for the YAML parse error (Closes #577).

One heads-up: this is a duplicate of PR #578 by @NY1024 — both change the exact same line in agent-scan/agent_scan/prompt/skills/agentic-supply-chain-detection/SKILL.md to the same quoted value. To avoid two PRs competing over the same file, could you two coordinate and keep a single one? Either is functionally correct; NY1024's PR also includes the root-cause analysis in its description, but whichever you prefer is fine. Once one is merged, the other should be closed. Thanks!