feat: Phase 8 — Network Discovery + Windows Dev-Setup-Skripte

Network Discovery:
- Go Agent: internal/scanner/scanner.go mit TCP-Sweep (Port 445/80/22/443),
  ARP-Tabellen-Parser (Windows: arp -a, Linux: /proc/net/arp), Reverse-DNS,
  50 gleichzeitige Goroutines mit Semaphore
- Go Agent main.go: COMMAND_TYPE_NETWORK_SCAN Case → scanner.Scan() → JSON stdout
- Backend: NetworkDevice Model (Id, AgentId, IpAddress, MacAddress, Hostname,
  Vendor, IsManaged, FirstSeen, LastSeen)
- Backend: EF Migration AddNetworkDevices + Index auf IpAddress + MacAddress
- Backend: NetworkDevicesController GET /api/v1/network-devices + DELETE /{id}
- Backend: AgentGrpcService.ProcessNetworkScanResultAsync — upsert via MAC,
  IsManaged=true wenn IP einem bekannten Agent entspricht
- Frontend: NetworkPage.tsx mit Scan-Panel, Device-Tabelle, Filter, Delete
- Frontend: App.tsx — 'Netzwerk' Nav-Eintrag mit Network Icon

Windows Dev-Setup:
- dev-start.ps1 — Startet Docker/Postgres, EF-Migrationen, Backend+Frontend
  in separaten PowerShell-Fenstern; Voraussetzungen-Check (docker/dotnet/node/go)
- dev-stop.ps1 — Stoppt alle NexusRMM-Prozesse + PostgreSQL Container
- build-agent.ps1 — Baut nexus-agent.exe (Windows) + optional nexus-agent-linux

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Frontend/src/App.tsx

@@ -1,11 +1,12 @@
 import { useState } from 'react'
 import { QueryClient, QueryClientProvider } from '@tanstack/react-query'
-import { LayoutDashboard, Ticket, Bell, Package, Menu, X } from 'lucide-react'
+import { LayoutDashboard, Ticket, Bell, Package, Network, Menu, X } from 'lucide-react'
 import { DashboardPage } from './pages/DashboardPage'
 import { AgentDetailPage } from './pages/AgentDetailPage'
 import TicketsPage from './pages/TicketsPage'
 import AlertsPage from './pages/AlertsPage'
 import SoftwarePage from './pages/SoftwarePage'
+import NetworkPage from './pages/NetworkPage'
 import { cn } from './lib/utils'
 
 const queryClient = new QueryClient({
@@ -17,7 +18,7 @@ const queryClient = new QueryClient({
   },
 })
 
-type Page = 'dashboard' | 'agent-detail' | 'tickets' | 'alerts' | 'software'
+type Page = 'dashboard' | 'agent-detail' | 'tickets' | 'alerts' | 'network' | 'software'
 
 interface NavItem {
   id: Page
@@ -29,6 +30,7 @@ const navItems: NavItem[] = [
   { id: 'dashboard', label: 'Dashboard', icon: <LayoutDashboard size={18} /> },
   { id: 'tickets', label: 'Tickets', icon: <Ticket size={18} /> },
   { id: 'alerts', label: 'Alerts', icon: <Bell size={18} /> },
+  { id: 'network', label: 'Netzwerk', icon: <Network size={18} /> },
   { id: 'software', label: 'Software', icon: <Package size={18} /> },
 ]
 
@@ -112,6 +114,7 @@ function AppContent() {
         )}
         {page === 'tickets' && <TicketsPage />}
         {page === 'alerts' && <AlertsPage />}
+        {page === 'network' && <NetworkPage />}
         {page === 'software' && <SoftwarePage />}
       </main>
     </div>

Frontend/src/api/client.ts

@@ -15,6 +15,7 @@ import type {
   DeployRequest,
   DeployResponse,
   RemoteSessionInfo,
+  NetworkDevice,
 } from './types'
 
 const BASE_URL = '/api/v1'
@@ -104,3 +105,22 @@ export const remoteDesktopApi = {
   getSession: (agentId: string) =>
     request<RemoteSessionInfo>(`/agents/${agentId}/remote-session`),
 }
+
+// Network Devices
+export const networkDevicesApi = {
+  list: (agentId?: string) => {
+    const param = agentId ? `?agentId=${agentId}` : ''
+    return request<NetworkDevice[]>(`/network-devices${param}`)
+  },
+  delete: (id: number) =>
+    request<void>(`/network-devices/${id}`, { method: 'DELETE' }),
+}
+
+// Network Scan triggern (nutzt tasksApi intern)
+export const networkScanApi = {
+  trigger: (agentId: string, subnet?: string) =>
+    request<TaskItem>('/tasks', {
+      method: 'POST',
+      body: JSON.stringify({ agentId, type: 'NetworkScan', payload: { subnet: subnet ?? '' } }),
+    }),
+}

Frontend/src/api/types.ts

@@ -184,3 +184,15 @@ export interface RemoteSessionInfo {
   sessionUrl?: string
   meshCentralBaseUrl?: string
 }
+
+export interface NetworkDevice {
+  id: number
+  agentId: string | null
+  ipAddress: string
+  macAddress: string
+  hostname: string
+  vendor: string
+  isManaged: boolean
+  firstSeen: string
+  lastSeen: string
+}

Frontend/src/pages/NetworkPage.tsx

@@ -0,0 +1,285 @@
+import { useState } from 'react'
+import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query'
+import { Network, Trash2, Play, Wifi, WifiOff } from 'lucide-react'
+import { networkDevicesApi, networkScanApi } from '../api/client'
+import { cn } from '../lib/utils'
+
+function formatRelativeTime(dateString: string): string {
+  const now = new Date()
+  const date = new Date(dateString)
+  const diffMs = now.getTime() - date.getTime()
+
+  const diffSeconds = Math.floor(diffMs / 1000)
+  const diffMinutes = Math.floor(diffSeconds / 60)
+  const diffHours = Math.floor(diffMinutes / 60)
+  const diffDays = Math.floor(diffHours / 24)
+
+  if (diffSeconds < 60) {
+    return 'gerade eben'
+  }
+  if (diffMinutes < 60) {
+    return `vor ${diffMinutes} Min.`
+  }
+  if (diffHours < 24) {
+    return `vor ${diffHours} Std.`
+  }
+  return `vor ${diffDays} Tagen`
+}
+
+export default function NetworkPage() {
+  const [agentIdInput, setAgentIdInput] = useState('')
+  const [subnetInput, setSubnetInput] = useState('')
+  const [filterUnknown, setFilterUnknown] = useState(false)
+  const [isScanPending, setIsScanPending] = useState(false)
+
+  const queryClient = useQueryClient()
+
+  const devicesQuery = useQuery({
+    queryKey: ['networkDevices'],
+    queryFn: () => networkDevicesApi.list(),
+  })
+
+  const scanMutation = useMutation({
+    mutationFn: ({ agentId, subnet }: { agentId: string; subnet?: string }) =>
+      networkScanApi.trigger(agentId, subnet),
+    onSuccess: () => {
+      setIsScanPending(true)
+      // Refresh after a brief delay to show updated results
+      setTimeout(() => {
+        queryClient.invalidateQueries({ queryKey: ['networkDevices'] })
+        setIsScanPending(false)
+      }, 3000)
+    },
+    onError: () => {
+      setIsScanPending(false)
+    },
+  })
+
+  const deleteMutation = useMutation({
+    mutationFn: (id: number) => networkDevicesApi.delete(id),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ['networkDevices'] })
+    },
+  })
+
+  const handleScan = () => {
+    if (!agentIdInput.trim()) return
+    setIsScanPending(true)
+    scanMutation.mutate({
+      agentId: agentIdInput.trim(),
+      subnet: subnetInput.trim() || undefined,
+    })
+  }
+
+  const handleDelete = (id: number) => {
+    if (window.confirm('Möchten Sie dieses Gerät wirklich löschen?')) {
+      deleteMutation.mutate(id)
+    }
+  }
+
+  const devices = devicesQuery.data ?? []
+  const filteredDevices = filterUnknown
+    ? devices.filter((d) => !d.isManaged)
+    : devices
+
+  return (
+    <div className="space-y-6 p-6">
+      {/* Header */}
+      <div className="flex items-center gap-3">
+        <Network size={24} className="text-primary" />
+        <div>
+          <h1 className="text-3xl font-bold text-foreground">Netzwerk-Discovery</h1>
+          <p className="text-muted-foreground text-sm mt-1">
+            Geräte im Netzwerk erkennen und verwalten
+          </p>
+        </div>
+      </div>
+
+      {/* Scan Panel */}
+      <div className="bg-card border border-border rounded-lg p-6">
+        <h2 className="text-lg font-semibold text-foreground mb-4">Netzwerk-Scan starten</h2>
+        <div className="flex flex-col sm:flex-row gap-3">
+          <input
+            type="text"
+            value={agentIdInput}
+            onChange={(e) => setAgentIdInput(e.target.value)}
+            placeholder="Agent-ID (erforderlich)"
+            className="flex-1 bg-background border border-border rounded-lg px-3 py-2 text-foreground placeholder-muted-foreground focus:outline-none focus:ring-2 focus:ring-primary"
+          />
+          <input
+            type="text"
+            value={subnetInput}
+            onChange={(e) => setSubnetInput(e.target.value)}
+            placeholder="Subnetz (optional, z.B. 192.168.1.0/24)"
+            className="flex-1 bg-background border border-border rounded-lg px-3 py-2 text-foreground placeholder-muted-foreground focus:outline-none focus:ring-2 focus:ring-primary"
+          />
+          <button
+            onClick={handleScan}
+            disabled={!agentIdInput.trim() || scanMutation.isPending || isScanPending}
+            className={cn(
+              'flex items-center gap-2 bg-primary text-primary-foreground px-4 py-2 rounded-lg hover:bg-primary/90 transition-colors disabled:opacity-50 disabled:cursor-not-allowed whitespace-nowrap',
+            )}
+          >
+            <Play size={16} />
+            {isScanPending ? 'Scan läuft...' : 'Scan starten'}
+          </button>
+        </div>
+        {scanMutation.isError && (
+          <p className="text-red-400 text-sm mt-2">
+            Fehler beim Starten des Scans: {String(scanMutation.error)}
+          </p>
+        )}
+        {isScanPending && !scanMutation.isError && (
+          <p className="text-muted-foreground text-sm mt-2 flex items-center gap-2">
+            <span className="inline-block w-2 h-2 rounded-full bg-primary animate-pulse" />
+            Scan wurde gestartet. Ergebnisse werden in Kürze aktualisiert...
+          </p>
+        )}
+      </div>
+
+      {/* Results Table */}
+      <div className="bg-card border border-border rounded-lg p-6">
+        <div className="flex items-center justify-between mb-4">
+          <h2 className="text-lg font-semibold text-foreground">
+            Erkannte Geräte
+            {devicesQuery.isSuccess && (
+              <span className="ml-2 text-sm font-normal text-muted-foreground">
+                ({filteredDevices.length} von {devices.length})
+              </span>
+            )}
+          </h2>
+
+          {/* Filter Toggle */}
+          <div className="flex gap-2">
+            <button
+              onClick={() => setFilterUnknown(false)}
+              className={cn(
+                'px-3 py-1 rounded text-sm transition-colors',
+                !filterUnknown
+                  ? 'bg-primary text-primary-foreground'
+                  : 'bg-accent text-foreground hover:bg-accent/80',
+              )}
+            >
+              Alle
+            </button>
+            <button
+              onClick={() => setFilterUnknown(true)}
+              className={cn(
+                'px-3 py-1 rounded text-sm transition-colors',
+                filterUnknown
+                  ? 'bg-primary text-primary-foreground'
+                  : 'bg-accent text-foreground hover:bg-accent/80',
+              )}
+            >
+              Nur unbekannte Geräte
+            </button>
+          </div>
+        </div>
+
+        {/* Loading State */}
+        {devicesQuery.isLoading && (
+          <p className="text-muted-foreground py-4">Lädt...</p>
+        )}
+
+        {/* Error State */}
+        {devicesQuery.isError && (
+          <p className="text-red-400 py-4">
+            Fehler beim Laden der Geräte
+          </p>
+        )}
+
+        {/* Empty State */}
+        {devicesQuery.isSuccess && filteredDevices.length === 0 && (
+          <div className="text-center py-12 text-muted-foreground">
+            <Network size={40} className="mx-auto mb-3 opacity-30" />
+            <p>
+              {filterUnknown
+                ? 'Keine unbekannten Geräte gefunden'
+                : 'Keine Geräte gefunden. Starten Sie einen Scan.'}
+            </p>
+          </div>
+        )}
+
+        {/* Table */}
+        {devicesQuery.isSuccess && filteredDevices.length > 0 && (
+          <div className="overflow-x-auto">
+            <table className="w-full text-sm">
+              <thead>
+                <tr className="bg-accent border-b border-border">
+                  <th className="px-4 py-3 text-left text-sm font-semibold text-muted-foreground">
+                    IP-Adresse
+                  </th>
+                  <th className="px-4 py-3 text-left text-sm font-semibold text-muted-foreground">
+                    MAC-Adresse
+                  </th>
+                  <th className="px-4 py-3 text-left text-sm font-semibold text-muted-foreground">
+                    Hostname
+                  </th>
+                  <th className="px-4 py-3 text-left text-sm font-semibold text-muted-foreground">
+                    Hersteller
+                  </th>
+                  <th className="px-4 py-3 text-left text-sm font-semibold text-muted-foreground">
+                    Status
+                  </th>
+                  <th className="px-4 py-3 text-left text-sm font-semibold text-muted-foreground">
+                    Zuletzt gesehen
+                  </th>
+                  <th className="px-4 py-3 text-left text-sm font-semibold text-muted-foreground">
+                    Aktion
+                  </th>
+                </tr>
+              </thead>
+              <tbody>
+                {filteredDevices.map((device) => (
+                  <tr
+                    key={device.id}
+                    className="border-b border-border hover:bg-card/50 transition-colors"
+                  >
+                    <td className="px-4 py-3 font-mono text-foreground">
+                      {device.ipAddress}
+                    </td>
+                    <td className="px-4 py-3 font-mono text-xs text-muted-foreground">
+                      {device.macAddress || '—'}
+                    </td>
+                    <td className="px-4 py-3 text-foreground">
+                      {device.hostname || '—'}
+                    </td>
+                    <td className="px-4 py-3 text-muted-foreground">
+                      {device.vendor || '—'}
+                    </td>
+                    <td className="px-4 py-3">
+                      {device.isManaged ? (
+                        <span className="inline-flex items-center gap-1 px-2 py-1 rounded text-xs font-medium bg-green-500/20 text-green-400 border border-green-500/30">
+                          <Wifi size={12} />
+                          Verwaltet
+                        </span>
+                      ) : (
+                        <span className="inline-flex items-center gap-1 px-2 py-1 rounded text-xs font-medium bg-muted/50 text-muted-foreground border border-border">
+                          <WifiOff size={12} />
+                          Unbekannt
+                        </span>
+                      )}
+                    </td>
+                    <td className="px-4 py-3 text-muted-foreground text-xs">
+                      {formatRelativeTime(device.lastSeen)}
+                    </td>
+                    <td className="px-4 py-3">
+                      <button
+                        onClick={() => handleDelete(device.id)}
+                        disabled={deleteMutation.isPending}
+                        className="flex items-center gap-1 px-2 py-1 rounded text-xs bg-red-500/20 text-red-400 hover:bg-red-500/30 transition-colors disabled:opacity-50"
+                      >
+                        <Trash2 size={12} />
+                        Löschen
+                      </button>
+                    </td>
+                  </tr>
+                ))}
+              </tbody>
+            </table>
+          </div>
+        )}
+      </div>
+    </div>
+  )
+}