Capture Smart Home Planner documentation app

## Summary
- Carlo asked to add this Reddit share to GitHub: https://www.reddit.com/r/homeassistant/comments/1rdw99f/smart_home_planner_home_assistant_app_to_document/
- The post is from u/smarthomecompared and promotes the Smart Home Planner Home Assistant add-on/app, which is meant to document the *physical* smart-home devices.
- Key capabilities: builds a rich device inventory (brands, labels, areas, floors, networks, power, warranty, etc.); syncs devices/labels/areas/floors with Home Assistant; supports floor-plan diagrams and bulk editing; lets you attach files to each device (manuals, invoices, photos); and exposes dashboards for batteries, connectivity, and maintenance views.
- Source repo: https://github.com/smarthomecompared/smart-home-planner

## Why it matters
- Could be a handy reference for backing up our own inventory and for recommending/documenting tools for larger installs.

## Next steps
- Decide if we should add this to a resources document, a Home Assistant showcase page, or otherwise track it for future evaluation.