Add tab icons and fix mobile dashboard styling issues

- Add matching lucide-react icons to tab/mode switcher buttons on
  payments, at-the-door, manual, email-attendees, whatsapp-attendees,
  and admin cashup pages, mirroring icons already used in their help menus
- Fix navbar Logout button sitting lower than other nav links (missing
  border/padding classes that other links use for their active-underline)
- Fix stat card labels getting truncated on mobile by removing the
  ellipsis-cut label and widening the mobile grid to one column
- Fix Revenue trend / Top performing events rendering outside the
  viewport on mobile by containing horizontal overflow and truncating
  long event titles in the table

frontend/src/app/dashboard/supervisor/page.tsx

@@ -101,7 +101,7 @@ export default function SupervisorDashboardPage() {
   }, 15000, !!token);
 
   return (
-    <div className="max-w-6xl mx-auto w-full">
+    <div className="max-w-6xl mx-auto w-full overflow-x-hidden">
       <div className="mb-6">
         <h1 className="text-2xl font-semibold text-gray-900">Welcome back{user ? `, ${user.name}` : ""} 👋</h1>
         <p className="text-sm text-gray-500 mt-1">Here&apos;s what&apos;s happening with your events today.</p>
@@ -131,7 +131,7 @@ export default function SupervisorDashboardPage() {
       </div>
 
       <div className="grid lg:grid-cols-3 gap-6">
-        <div className="lg:col-span-2 space-y-6">
+        <div className="lg:col-span-2 space-y-6 min-w-0">
           <div className="border rounded-xl p-4 bg-white shadow-sm">
             <h2 className="text-lg font-semibold mb-3">Revenue trend — past month</h2>
             {overview && overview.trend.length > 0 ? (
@@ -156,7 +156,7 @@ export default function SupervisorDashboardPage() {
                 <TableBody>
                   {overview.topEvents.map(e => (
                     <TableRow key={e.eventId}>
-                      <TableCell className="font-medium">{e.title}</TableCell>
+                      <TableCell className="font-medium max-w-[140px] sm:max-w-[220px] truncate" title={e.title}>{e.title}</TableCell>
                       <TableCell className="text-right">{formatCount(e.registrations)}</TableCell>
                       <TableCell className="text-right">{formatRand(e.revenue)}</TableCell>
                       <TableCell className="text-right">{formatCount(e.ticketsSold)}</TableCell>
@@ -190,7 +190,7 @@ export default function SupervisorDashboardPage() {
           </div>
         </div>
 
-        <div className="space-y-6">
+        <div className="space-y-6 min-w-0">
           <div className="border rounded-xl p-4 bg-white shadow-sm">
             <div className="flex items-center justify-between mb-3">
               <h2 className="text-lg font-semibold">Scanner activity</h2>