Add Proxmox integration adapter with real resource listing

Implements testConnection (via /api2/json/version) and listResources
(via /api2/json/cluster/resources) using Proxmox's API token auth header,
following the same pattern as the Docker adapter. Verified end-to-end:
graceful failure against an unreachable host, correct event logging, and
exclusion from the resources endpoint when not connected.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BbJV5nm8KPVH1oNJYKpnoF

backend/src/integrations/proxmox.ts

@@ -0,0 +1,43 @@
+import type { IntegrationAdapter, Resource } from './types.js'
+
+interface ProxmoxResourceEntry {
+  type: string
+  name?: string
+  status?: string
+  vmid?: number
+  node?: string
+}
+
+function authHeader(apiKey: string): Record<string, string> {
+  return { Authorization: `PVEAPIToken=${apiKey}` }
+}
+
+export const proxmox: IntegrationAdapter = {
+  async testConnection(config, secrets) {
+    const baseUrl = config.baseUrl?.replace(/\/$/, '')
+    const apiKey = secrets.apiKey
+    if (!baseUrl) return { ok: false, message: 'Missing baseUrl' }
+    if (!apiKey) return { ok: false, message: 'Missing API token' }
+    try {
+      const res = await fetch(`${baseUrl}/api2/json/version`, { headers: authHeader(apiKey) })
+      if (!res.ok) return { ok: false, message: `HTTP ${res.status}` }
+      return { ok: true, message: 'Connected' }
+    } catch (err) {
+      return { ok: false, message: err instanceof Error ? err.message : 'Connection failed' }
+    }
+  },
+
+  async listResources(config, secrets): Promise<Resource[]> {
+    const baseUrl = config.baseUrl?.replace(/\/$/, '')
+    const apiKey = secrets.apiKey
+    if (!baseUrl || !apiKey) return []
+    const res = await fetch(`${baseUrl}/api2/json/cluster/resources?type=vm`, { headers: authHeader(apiKey) })
+    if (!res.ok) return []
+    const body = (await res.json()) as { data: ProxmoxResourceEntry[] }
+    return body.data.map((entry) => ({
+      name: entry.name ?? `vm-${entry.vmid}`,
+      status: entry.status === 'running' ? 'healthy' : entry.status === 'stopped' ? 'unknown' : 'warning',
+      detail: `${entry.type} on ${entry.node} — ${entry.status}`,
+    }))
+  },
+}

backend/src/integrations/registry.ts

@@ -1,6 +1,7 @@
 import type { IntegrationAdapter, IntegrationType } from './types.js'
 import { uptimeKuma } from './uptimeKuma.js'
 import { docker } from './docker.js'
+import { proxmox } from './proxmox.js'
 
 const notImplemented: IntegrationAdapter = {
   async testConnection() {
@@ -11,7 +12,7 @@ const notImplemented: IntegrationAdapter = {
 export const adapterRegistry: Record<IntegrationType, IntegrationAdapter> = {
   uptime_kuma: uptimeKuma,
   docker,
-  proxmox: notImplemented,
+  proxmox,
   netbird: notImplemented,
   cloudflare: notImplemented,
   aws: notImplemented,