Trial Network Graph
This network graph visualizes connections between apps and platforms, grouping nodes by their activity type. The force-directed layout uses `d3.forceSimulation` with link, charge, collision, and center forces to position nodes, while SVG circles and text labels render each entity. `scaleOrdinal` maps group categories to colors, and nodes are draggable with `d3.drag`, highlighting on mouseover. Links are drawn as lines with arrowhead markers defined in SVG `defs`. The example loads data from a local JSON file and runs entirely client-side with D3 v6.