[codex] Reframe Ghost fingerprint capture docs

[nahiyankhan]

Summary

• reframes Ghost scan/status docs and the installed skill around agent-led Fingerprint Capture
• adds scan readiness language for product-observed, component-demo, substrate-only, and unobservable bundles
• refreshes README/docs references for the unified @anarchitecture/ghost package and current .ghost bundle shape
• marks packages/ghost-scan as a private historical package and points users to the unified ghost CLI

Validation

• pnpm check
• pre-push hook: pnpm build, pnpm check, pnpm test

Note: local gh auth status reports an invalid token, so this PR was opened through the connected GitHub app.