docs: correct home router model to CRS309-1G-8S+IN

[jmgilman]

Summary

• The home router documented as a MikroTik CCR2004 is actually a second CRS309-1G-8S+IN (owner-confirmed; the provided purchase link resolves to the CRS309 listing, ASIN B07NFXN4SS)
• Inventory: CCR2004 entry removed; CRS309 quantity is now 2 with the purchase link
• Networking hardware table, physical connection map, and the lab v2 design draft updated; the two identical units are qualified as (home router) / (core switch) where ambiguous

Notes for reviewer

• PHY-001's recorded home-router port label SFP+ 1 was kept verbatim; worth re-checking against the chassis since the label style differs from the core unit's Port N rows

Validation

• grep -ri ccr2004 docs/docs is empty
• moon run docs:build (mkdocs --strict) passes