docs: complete Apricity usage wiki (15 pages)
Add a full how-to wiki based on the actual code: Home, Installation,
Tour, Browsing/Searching, Writing/Editing, Deleting/Recovering,
Knowledge Graph & Tunnels, Notifications, Settings, Keyboard Shortcuts,
Configuration, API Reference, Security, Troubleshooting/FAQ, plus a
sidebar. Endpoints, env vars, settings panes, and shortcuts verified
against the source.