fix: handle multi-IP and add tests for clickable IP link

Follow-up to #78:
- Use primaryIp() so href targets the first IP when data.ip is comma-separated (e.g. "192.168.1.1, 2001:db8::1")
- Add primaryIp() helper to maskIp.ts
- Add 4 tests covering single IP link, absent IP, multi-IP href, multi-IP display text

frontend/src/components/panels/DetailPanel.tsx

@@ -5,6 +5,7 @@ import { Input } from '@/components/ui/input'
 import { useCanvasStore } from '@/stores/canvasStore'
 import { NODE_TYPE_LABELS, STATUS_COLORS, type ServiceInfo, type NodeData, type NodeProperty } from '@/types'
 import { getServiceUrl } from '@/utils/serviceUrl'
+import { primaryIp } from '@/utils/maskIp'
 import { PROPERTY_ICONS, PROPERTY_ICON_NAMES, resolvePropertyIcon } from '@/utils/propertyIcons'
 import type { Node } from '@xyflow/react'
 
@@ -205,7 +206,7 @@ export function DetailPanel({ onEdit }: DetailPanelProps) {
         {data.ip && (
           <div className="flex justify-between gap-2 items-baseline">
             <span className="text-muted-foreground text-xs shrink-0">IP Address</span>
-            <a href={`http://${data.ip}`} target="_blank" rel="noopener noreferrer" className="text-xs font-mono text-[#00d4ff] hover:underline truncate flex items-center gap-1" title={data.ip}>
+            <a href={`http://${primaryIp(data.ip)}`} target="_blank" rel="noopener noreferrer" className="text-xs font-mono text-[#00d4ff] hover:underline truncate flex items-center gap-1" title={data.ip}>
               {data.ip}<ExternalLink size={10} className="shrink-0" />
             </a>
           </div>