Add Blazor Server reconnection modal and timer functionality

DiunaBI.UI.Web/wwwroot/app.css

@@ -58,3 +58,93 @@ h1:focus {
 .mud-pagination li::marker {
   display: none;
 }
+
+/* Blazor Server Reconnection UI Customization */
+#components-reconnect-modal {
+    position: fixed;
+    top: 0;
+    left: 0;
+    right: 0;
+    bottom: 0;
+    background: rgba(0, 0, 0, 0.5);
+    backdrop-filter: blur(4px);
+    z-index: 9999;
+    font-family: 'Roboto', 'Helvetica Neue', Helvetica, Arial, sans-serif;
+    display: none !important;
+    align-items: center;
+    justify-content: center;
+}
+
+/* Show modal when Blazor applies these classes */
+#components-reconnect-modal.components-reconnect-show,
+#components-reconnect-modal.components-reconnect-failed,
+#components-reconnect-modal.components-reconnect-rejected {
+    display: flex !important;
+}
+
+#components-reconnect-modal .reconnect-content {
+    background: white;
+    border-radius: 8px;
+    padding: 32px;
+    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.2);
+    max-width: 400px;
+    text-align: center;
+}
+
+#components-reconnect-modal h5 {
+    margin: 0 0 16px 0;
+    color: #424242;
+    font-size: 20px;
+    font-weight: 500;
+}
+
+#components-reconnect-modal .reconnect-message {
+    color: #666;
+    margin-bottom: 24px;
+    font-size: 14px;
+    line-height: 1.5;
+}
+
+#components-reconnect-modal .reconnect-spinner {
+    width: 48px;
+    height: 48px;
+    border: 4px solid #f3f3f3;
+    border-top: 4px solid #e7163d;
+    border-radius: 50%;
+    animation: spin 1s linear infinite;
+    margin: 0 auto 16px;
+}
+
+@keyframes spin {
+    0% { transform: rotate(0deg); }
+    100% { transform: rotate(360deg); }
+}
+
+#components-reconnect-modal .reconnect-timer {
+    color: #e7163d;
+    font-size: 16px;
+    font-weight: 500;
+    margin-bottom: 16px;
+}
+
+#components-reconnect-modal button {
+    background-color: #e7163d;
+    color: white;
+    border: none;
+    border-radius: 4px;
+    padding: 10px 24px;
+    font-size: 14px;
+    font-weight: 500;
+    cursor: pointer;
+    transition: background-color 0.2s;
+    text-transform: uppercase;
+    letter-spacing: 0.5px;
+}
+
+#components-reconnect-modal button:hover {
+    background-color: #c01234;
+}
+
+#components-reconnect-modal button:active {
+    background-color: #a01028;
+}