fix(web): allow MazeNET canvas pan from inside net-box body

Pan drag previously required mousedown on the bare canvas (target ===
currentTarget). When zoomed in, net-boxes cover most of the viewport
so there was no bare grid to grab. Drop the guard — node/header/port/
resize handlers all call stopPropagation() already, so only net-box
body mousedowns bubble up to start the pan, which is exactly what
we want.

decnet_web/src/components/MazeNET/useMazeInteraction.ts

@@ -87,7 +87,10 @@ export function useMazeInteraction({ nets, nodes, setNets, setNodes, canvasRef,
 
   const onCanvasMouseDown = useCallback((e: React.MouseEvent) => {
     if (e.button !== 0) return;
-    if (e.target !== e.currentTarget) return;
+    // Pan starts whenever a left-mousedown bubbles up to the canvas.
+    // Node/header/resize/port handlers call stopPropagation() and never
+    // reach here; net-box body mousedowns DO bubble so you can pan from
+    // "inside" a LAN when zoomed in and no bare grid is visible.
     setDrag({ type: 'pan', startX: e.clientX, startY: e.clientY, panX: panRef.current.x, panY: panRef.current.y });
   }, []);