Port icon grid and entity picker patterns from wled-screen-controller.
IconGrid replaces plain <select> elements with visual icon grids for
known item sets (widget type, icon type, healthcheck method, permission
level). EntityPicker replaces search dropdowns with a command-palette
style overlay with keyboard navigation and filtering.
Enhance SearchDialog with keyboard navigation (arrow keys, Enter,
Escape), grouped results with section headers, active highlight,
and a footer with shortcut hints.
alexei.dolgolyov