feat: Introduce and integrate a mobile back button component across agent and user profile pages.

src/app/(user)/user/profile/[id]/page.tsx

@@ -16,6 +16,7 @@ import {
   ContactInfo,
 } from '@/components/profile';
 import { ConnectRequestModal } from '@/components/modals';
+import { MobileBackButton } from '@/components/layout/MobileBackButton';
 import { agentsService, AgentProfile, FieldValueResponse } from '@/services/agents.service';
 import { connectionRequestsService, ConnectionStatus } from '@/services/connection-requests.service';
 import { uploadService } from '@/services/upload.service';
@@ -277,6 +278,7 @@ export default function AgentProfileView() {
 
   return (
     <div className="max-w-7xl mx-auto px-4 lg:px-8 py-6 space-y-6">
+      <MobileBackButton label="Back" fallbackHref="/user/profiles" />
       {/* Main Layout - Responsive: Column on mobile, Row on desktop */}
       <div className="flex flex-col lg:flex-row gap-6 lg:items-stretch">
         {/* Left Sidebar - Status & Contact */}