feat: add hide IP toggle in sidebar

- Add hideIp / toggleHideIp to canvasStore (UI-only, not persisted)
- Add maskIp util: 192.168.1.115 → 192.168.XX.XX (non-IPv4 passthrough)
- BaseNode reads hideIp from store and masks last two octets when active
- Sidebar shows Eye/EyeOff toggle below Scan Network, highlights when active

frontend/src/stores/canvasStore.ts

@@ -35,6 +35,8 @@ interface CanvasState {
   markUnsaved: () => void
   loadCanvas: (nodes: Node<NodeData>[], edges: Edge<EdgeData>[]) => void
   notifyScanDeviceFound: () => void
+  hideIp: boolean
+  toggleHideIp: () => void
 }
 
 export const useCanvasStore = create<CanvasState>((set) => ({
@@ -43,6 +45,7 @@ export const useCanvasStore = create<CanvasState>((set) => ({
   hasUnsavedChanges: false,
   selectedNodeId: null,
   editingGroupRectId: null,
+  hideIp: false,
   scanEventTs: 0,
 
   onNodesChange: (changes) =>
@@ -160,6 +163,9 @@ export const useCanvasStore = create<CanvasState>((set) => ({
 
   notifyScanDeviceFound: () => set({ scanEventTs: Date.now() }),
 
+  hideIp: false,
+  toggleHideIp: () => set((s) => ({ hideIp: !s.hideIp })),
+
   loadCanvas: (nodes, edges) => {
     // React Flow requires parents before children in the array
     const parents = nodes.filter((n) => !n.parentId)