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/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
+}