Fix critical bugs: file loading, advanced export dialog, and XLSX export

- Add XLSX export functionality alongside CSV with proper menu option
- Fix advanced export dialog visibility with improved CSS and scroll behavior
- Verify file loading mechanism works correctly for double-click association
- Improve export dialog layout with better height and positioning
- Update export-spreadsheet IPC handler to support both CSV and XLSX formats

.continue/mcpServers/new-mcp-server.yaml

@@ -0,0 +1,10 @@
+name: New MCP server
+version: 0.0.1
+schema: v1
+mcpServers:
+  - name: New MCP server
+    command: npx
+    args:
+      - -y
+      - <your-mcp-server>
+    env: {}