feat(export): show spinner in load detail in-progress status

src/pages/ExportPage.scss

@@ -228,6 +228,19 @@
   }
 }
 
+.session-load-detail-status-cell {
+  display: inline-flex;
+  align-items: center;
+  justify-content: flex-start;
+  gap: 6px;
+  min-width: 0;
+}
+
+.session-load-detail-status-icon {
+  color: var(--text-tertiary);
+  flex-shrink: 0;
+}
+
 .global-export-controls {
   background: var(--card-bg);
   border: 1px solid var(--border-color);