fix(awg): reserve server gateway IP (.1) in client IP assignment

Previously only .0 was reserved, causing first client to get 10.8.1.1 (server IP).
Now both .0 and .1 are reserved, clients start from 10.8.1.2.

inc/VpnClient.php

@@ -623,8 +623,8 @@ class VpnClient
         $stmt->execute([$serverData['id']]);
         $usedIPs = $stmt->fetchAll(PDO::FETCH_COLUMN);
 
-        // Reserve network address
+        // Reserve network address and server gateway (.1)
-        $used = ['10.8.1.0' => true];
+        $used = ['10.8.1.0' => true, '10.8.1.1' => true];
         foreach ($usedIPs as $ip) {
             $used[$ip] = true;
         }