Add homelab replication quickstart

[keepittechie]

Summary

• Added a public-safe replication quickstart
• Explained how readers can build a similar homelab pattern in phases
• Added beginner options and later upgrade paths
• Clarified what should be documented privately versus shared publicly
• Linked the quickstart from README and major navigation docs

Safety Review

• Markdown link check passed
• Diagram structure check passed
• Public-safety scan passed
• git diff --check passed
• Old episode/video companion terms scan returned clean
• Private domain scan returned clean
• Personal path/email scan returned clean
• Private-language scan returned clean
• No screenshots, exact host IPs, private domains, raw exports, credentials, or private data were added

Notes

This keeps the repo focused on homelab setup and safe replication patterns.