docs: full feature documentation sweep — 12 new domain pages + Home index The wiki covered install/ops/plugins but had zero feature docs. Added user/operator-facing pages for every nav domain (jobs & dispatch, sales & estimating, invoicing & payments, customers & comms, customer portal, tech mobile app, catalogs, inventory & purchasing, accounting/payroll/reports, marketing & retention, integrations, admin & settings) plus a Feature Overview map. Rewrote Home as the index; replaced the stale plugin build-status table with a current summary; de-hardcoded the v1.0.0 release reference in Updating. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>