feat(frontend): add page titles to navbar on mobile

- Save vertical space on mobile by showing page title in navbar
- Mobile: "spotlight.cam - {PageTitle}" instead of separate h1
- Desktop: unchanged - page titles remain as separate headings
- Saves ~60-80px vertical space on mobile devices

Pages updated:
- Dashboard, Events, Matches, History, Profile

frontend/src/pages/DashboardPage.jsx

@@ -160,9 +160,9 @@ const DashboardPage = () => {
   const hasOutgoing = matchRequests?.outgoing?.length > 0;
 
   return (
-    <Layout>
+    <Layout pageTitle="Dashboard">
       <div className="max-w-5xl mx-auto">
-        <div className="mb-8">
+        <div className="hidden lg:block mb-8">
           <h1 className="text-3xl font-bold text-gray-900">Dashboard</h1>
           <p className="text-gray-600 mt-1">
             Welcome back, {user?.firstName || user?.username}!