Enhance Proxmox views with improved loading states and UI updates

- Updated serverplaceholder.blade.php to enhance loading skeletons for server details.
- Added navigation breadcrumbs to statistics, subdomain, and system views for better user experience.
- Improved loading indicators for CPU, network, memory, and disk charts in statistics.blade.php.
- Refined storage.blade.php layout with section dividers and improved drive display, including bus type indicators and quota usage.
- Enhanced VNC and Xterm popups with a new header design, loading animations, and reconnect functionality.
- Added error handling for VNC and Xterm connections to inform users when unable to connect.

extensions/Servers/Proxmox/views/vnc.blade.php

@@ -1,4 +1,10 @@
 <x-proxmox::layout :server="$server" view="vnc" :status="$status" :status-polling="true" :status-polling-interval="'2s'">
 
-    <iframe src="{{ $vnc }}" class="w-full min-h-800px border-0" height="800px"></iframe>
+    @if($vnc)
+        <iframe src="{{ $vnc }}" class="w-full min-h-800px border-0" height="800px"></iframe>
+    @else
+        <div class="flex items-center justify-center p-8 text-base/50">
+            <span>Unable to connect to VNC console. Please try again later.</span>
+        </div>
+    @endif
 </x-proxmox::layout>