fix: context menu dismisses on pane click, ISP in toolbar

Context menu now closes when clicking anywhere on the canvas via
onPaneClick prop. ISP device added as built-in toolbar item under
Internet section so it's always available without a database entry.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/components/network/NetworkCanvas.tsx

@@ -28,6 +28,7 @@ interface NetworkCanvasProps {
   isDragOver?: boolean
   onNodeContextMenu?: (event: React.MouseEvent, node: Node) => void
   onPaneContextMenu?: (event: MouseEvent | React.MouseEvent) => void
+  onPaneClick?: () => void
 }
 
 export function NetworkCanvas({
@@ -44,6 +45,7 @@ export function NetworkCanvas({
   isDragOver,
   onNodeContextMenu,
   onPaneContextMenu,
+  onPaneClick: onPaneClickProp,
 }: NetworkCanvasProps) {
   const handleSelectionChange = useCallback(({ nodes: selectedNodes, edges: selectedEdges }: { nodes: Node[]; edges: Edge[] }) => {
     if (selectedNodes.length === 1) {
@@ -61,7 +63,8 @@ export function NetworkCanvas({
   const handlePaneClick = useCallback(() => {
     onNodeSelect(null)
     onEdgeSelect(null)
-  }, [onNodeSelect, onEdgeSelect])
+    onPaneClickProp?.()
+  }, [onNodeSelect, onEdgeSelect, onPaneClickProp])
 
   return (
     <div className="relative h-full w-full" onDragLeave={onDragLeave}>