fix: correct UTC timestamp display and pre-existing code quality issues

frontend/src/components/modals/PendingDeviceModal.tsx

@@ -78,7 +78,7 @@ export function PendingDeviceModal({ device, onClose, onApprove, onHide, onIgnor
 
   const TypeIcon = TYPE_ICONS[device.suggested_type ?? 'generic'] ?? Circle
 
-  const handleApprove = () => { onApprove(device); onClose() }
+  const handleApprove = () => { onApprove(device) }
   const handleHide = () => { onHide(device); onClose() }
   const handleIgnore = () => { onIgnore(device); onClose() }
 

frontend/src/components/modals/__tests__/PendingDeviceModal.test.tsx

@@ -126,7 +126,7 @@ describe('PendingDeviceModal', () => {
 
   // ── Actions ───────────────────────────────────────────────────────────────
 
-  it('calls onApprove with the device and onClose when Approve is clicked', () => {
+  it('calls onApprove with the device when Approve is clicked (parent controls close on success)', () => {
     const device = makeDevice()
     const onApprove = vi.fn()
     const onClose = vi.fn()
@@ -135,7 +135,7 @@ describe('PendingDeviceModal', () => {
     )
     fireEvent.click(screen.getByRole('button', { name: 'Approve' }))
     expect(onApprove).toHaveBeenCalledWith(device)
-    expect(onClose).toHaveBeenCalledOnce()
+    expect(onClose).not.toHaveBeenCalled()
   })
 
   it('calls onHide with the device and onClose when Hide is clicked', () => {

frontend/src/components/panels/DetailPanel.tsx

@@ -85,6 +85,7 @@ export function DetailPanel({ onEdit }: DetailPanelProps) {
   const handleAddService = () => {
     const port = parseInt(newSvc.port, 10)
     if (!newSvc.service_name.trim() || isNaN(port) || port < 1 || port > 65535) return
+    snapshotHistory()
     const svc: ServiceInfo = { port, protocol: newSvc.protocol, service_name: newSvc.service_name.trim() }
     updateNode(node.id, { services: [...services, svc] })
     setNewSvc(EMPTY_FORM)
@@ -92,6 +93,7 @@ export function DetailPanel({ onEdit }: DetailPanelProps) {
   }
 
   const handleRemoveService = (index: number) => {
+    snapshotHistory()
     const updated = services.filter((_, i) => i !== index)
     updateNode(node.id, { services: updated })
     if (editingIndex === index) setEditingFor(null)
@@ -109,6 +111,7 @@ export function DetailPanel({ onEdit }: DetailPanelProps) {
     if (editingIndex === null) return
     const port = parseInt(editSvc.port, 10)
     if (!editSvc.service_name.trim() || isNaN(port) || port < 1 || port > 65535) return
+    snapshotHistory()
     const updated = services.map((svc, i) =>
       i === editingIndex ? { ...svc, port, protocol: editSvc.protocol, service_name: editSvc.service_name.trim() } : svc
     )

frontend/src/components/panels/Sidebar.tsx

@@ -163,6 +163,8 @@ export function Sidebar({ onAddNode, onAddGroupRect, onScan, onSave, onNodeAppro
   )
 }
 
+const COMMON_PORTS = new Set([22, 80, 443])
+
 function PendingDevicesPanel({ onNodeApproved, highlightId }: { onNodeApproved: (nodeId: string) => void; highlightId?: string }) {
   const [devices, setDevices] = useState<PendingDevice[]>([])
   const [loading, setLoading] = useState(false)
@@ -223,6 +225,7 @@ function PendingDevicesPanel({ onNodeApproved, highlightId }: { onNodeApproved:
       })
       toast.success(`Approved ${nodeData.label}`)
       setDevices((prev) => prev.filter((d) => d.id !== device.id))
+      setSelected(null)
       onNodeApproved(nodeId)
     } catch {
       toast.error('Failed to approve device')
@@ -269,7 +272,6 @@ function PendingDevicesPanel({ onNodeApproved, highlightId }: { onNodeApproved:
           <p className="text-xs text-muted-foreground text-center py-4">No pending devices</p>
         )}
         {devices.map((d) => {
-          const COMMON_PORTS = new Set([22, 80, 443])
           const namedService = d.services.find((s) => s.category != null && !COMMON_PORTS.has(s.port))
           const titleService = namedService
             ?? d.services.find((s) => s.port === 80)