Add Blazor Server reconnection modal and timer functionality

DiunaBI.UI.Web/Components/App.razor

@@ -31,9 +31,24 @@
     <a class="dismiss">🗙</a>
 </div>
 
+<div id="components-reconnect-modal" data-nosnippet>
+    <div class="reconnect-content">
+        <div class="reconnect-spinner"></div>
+        <h5>Connection Lost</h5>
+        <div class="reconnect-message">
+            Attempting to reconnect to the server...
+        </div>
+        <div class="reconnect-timer">
+            <span id="reconnect-elapsed-time">0s</span>
+        </div>
+        <button onclick="location.reload()">Reload Page</button>
+    </div>
+</div>
+
 <script src="_framework/blazor.web.js"></script>
 <script src="_content/MudBlazor/MudBlazor.min.js"></script>
 <script src="_content/DiunaBI.UI.Shared/js/auth.js"></script>
+<script src="js/reconnect.js"></script>
 </body>
 
 </html>