Restyle to light content theme with Lucide icons

- index.css: light body (#f4f5f7), white cards, sidebar stays dark navy
- AppIcon.tsx: Lucide icon lookup component for app tiles and nav
- Sidebar.tsx: Lucide nav icons (LayoutGrid, Users, Activity, LogOut)
- Dashboard.tsx: white cards with shadows, coloured Lucide app icons
- AdminMonitor.tsx: light theme throughout, Lucide tab icons,
  better status colours for light backgrounds

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/components/AppIcon.tsx

@@ -0,0 +1,27 @@
+import {
+  ClipboardList, ChefHat, Banknote, BedDouble, TrendingUp, Tag,
+  LayoutGrid, Users, Activity, Home, ScrollText, RefreshCw,
+  ArrowUpCircle, Wifi, Terminal, Settings, Building2,
+} from 'lucide-react'
+import type { LucideProps } from 'lucide-react'
+
+type IconComponent = React.ComponentType<LucideProps>
+
+const iconMap: Record<string, IconComponent> = {
+  ClipboardList, ChefHat, Banknote, BedDouble, TrendingUp, Tag,
+  LayoutGrid, Users, Activity, Home, ScrollText, RefreshCw,
+  ArrowUpCircle, Wifi, Terminal, Settings, Building2,
+}
+
+interface Props {
+  name: string
+  size?: number
+  color?: string
+  strokeWidth?: number
+}
+
+export function AppIcon({ name, size = 20, color, strokeWidth = 1.75 }: Props) {
+  const Icon = iconMap[name]
+  if (!Icon) return null
+  return <Icon size={size} color={color} strokeWidth={strokeWidth} />
+}