Guide cleanup and documentation updates
The guide section was cleaned up so the public pages are easier to read and maintain.
The guide section got a cleanup.
The main public guides are now organized around Getting Started, Recommended Settings, MeshCore Basics, Meshtastic Basics, Sharing Safely, and Coverage. Some older pages were folded into those guides or removed so people do not have to chase the same information in multiple places.
Behind the scenes, project notes were also added or updated for observer work, MQTT and map planning, observed activity data, Discord planning, and website assets.
The goal is to keep the public site useful for normal visitors while keeping the more technical project notes in the docs where they belong.