Adds touch double-tap detection to the node drag hook, enabling mobile-friendly interactions on the graph canvas, with coverage in the node drag and GraphTaskNode test suites.
Fusion-Task-Id: FN-4225
Separates graph panning from selection-gated drag by updating `useNodeDrag` and `useGraphInteraction` hooks to handle the two interaction modes independently, with `GraphTaskNode` now gating drag on selection state. Tests were added across the graph interaction, node drag, persistence, and integrati
Fusion-Task-Id: FN-3941
Adds draggable interaction to dependency graph nodes (FN-3089), introducing a `useNodeDrag` hook to manage drag state and positioning, with corresponding tests and a new drag stylesheet; the `GraphTaskNode` and `DependencyGraph` components are updated to wire up the drag behavior.
Fusion-Task-Id: FN-3089
