fix: add null/false guards, proper error handling, and VNC popup fix

- Add isset() guards before count() on ipv4/ipv6 arrays in ServerResource
  to prevent PHP 8.0+ TypeError
- Add null checks after getWhmcsService() and getCP() in 18 Module methods
  and 5 ModuleFunctions methods to prevent fatal null dereference errors
- Add null guards for $whmcsService and $cp in admin.php impersonateServerOwner
- Fix HTTP status codes throughout admin.php (404, 400, 500, 502 instead of 200)
- Guard ConfigureService methods against $this->cp === false
- Use null coalescing for customfields access in initServerBuild
- Check API response code in initServerBuild instead of always returning true
- Replace exit() with RuntimeException in Curl.php
- Change catch(Exception) to catch(Throwable) in hooks.php for PHP 8.0+
- Open VNC window before AJAX call to avoid popup blocker

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

modules/servers/VirtFusionDirect/lib/ServerResource.php

@@ -56,14 +56,14 @@ class ServerResource
                         $data['primaryNetwork']['mac'] = $server['network']['interfaces'][0]['mac'];
                     }
 
-                    if (count($server['network']['interfaces'][0]['ipv4'])) {
+                    if (isset($server['network']['interfaces'][0]['ipv4']) && count($server['network']['interfaces'][0]['ipv4'])) {
                         $data['primaryNetwork']['ipv4'] = [];
                         foreach ($server['network']['interfaces'][0]['ipv4'] as $ip) {
                             $data['primaryNetwork']['ipv4'][] = $ip['address'];
                         }
                     }
 
-                    if (count($server['network']['interfaces'][0]['ipv6'])) {
+                    if (isset($server['network']['interfaces'][0]['ipv6']) && count($server['network']['interfaces'][0]['ipv6'])) {
                         $data['primaryNetwork']['ipv6'] = [];
                         foreach ($server['network']['interfaces'][0]['ipv6'] as $ip) {
                             $data['primaryNetwork']['ipv6'][] = $ip['subnet'] . '/' . $ip['cidr'];