Added UI and functionality for profiles

set_profile.php

@@ -0,0 +1,30 @@
+<?php
+require 'db.php';
+require 'auth.php';
+
+header('Content-Type: application/json');
+require_login();
+
+$user_id = current_user_id();
+
+$input = json_decode(file_get_contents('php://input'), true);
+$profile_id = (int)($input['profile_id'] ?? 0);
+
+if ($profile_id <= 0) {
+  http_response_code(400);
+  echo json_encode(['success' => false, 'error' => 'Invalid profile_id']);
+  exit;
+}
+
+$stmt = $pdo->prepare("SELECT id FROM profiles WHERE id = ? AND user_id = ?");
+$stmt->execute([$profile_id, $user_id]);
+
+if (!$stmt->fetchColumn()) {
+  http_response_code(403);
+  echo json_encode(['success' => false, 'error' => 'Profile not allowed']);
+  exit;
+}
+
+$_SESSION['active_profile_id'] = $profile_id;
+
+echo json_encode(['success' => true, 'active_profile_id' => $profile_id]);