[codex] Rename fingerprint tool to Ghost Scan

[nahiyankhan]

Summary

• rename the fingerprint authoring package/CLI from ghost-fingerprint to ghost-scan
• fold the optional product-experience memory recipes into the ghost-scan skill bundle and remove ghost-memory
• keep the fingerprint bundle as the canonical product-experience memory artifact while preserving ghost-drift as the accountability layer

Details

This updates imports, workspace dependencies, docs, install metadata, changesets, CLI manifest generation, and tests to use ghost-scan. The .ghost/ artifact shape remains unchanged, including optional decisions/*.yml and proposals/*.yml.

Validation

• CI=true pnpm install
• pnpm build
• pnpm --filter ghost-scan build
• pnpm dump:cli-help
• pnpm test
• pnpm check
• git diff --check
• pre-push hook: pnpm build, pnpm check, pnpm test