Introduce a dedicated desktop layout overlay and auto-arrange features plus operator session endpoints. UI changes: add BD_icon_small.png, update .gitignore, add new overlay styles in desktop-mode.css, and rename widget snap CSS classes in desktop-widgets.css to avoid conflicts. JS updates: implement open/close layout overlay, autoArrangeWindows, shouldReserveTaskbarSpace, improved taskbar hide/toggle logic, and expose layout APIs from DesktopMode; widgets will call DesktopMode.openLayoutOverlay when available and otherwise use the widget picker. Backend changes: add requireOperatorRole middleware, helpers (normalizeSessionAction, toTimestamp, buildSessionHistory), enforce operator/admin checks on device/help-request endpoints, and add POST /api/bd/operator/sessions and GET /api/bd/operator/sessions to record and retrieve operator session history with input validation and duration computation.
UNITRONIX
