feat: add VPS Monitor backend and frontend services

- Create systemd service for VPS Monitor agent.
- Add FastAPI backend with endpoints for managing VPS configurations and statuses.
- Implement Dockerfile for backend service with required dependencies.
- Create frontend using React with Vite and Tailwind CSS for styling.
- Add API client for communicating with the backend.
- Implement components for displaying VPS information and logs.
- Set up Docker Compose for orchestrating backend and frontend services.
- Add environment configuration files for backend and agent.
- Implement CORS support in the backend for frontend communication.

vps-monitor/frontend/src/api/client.js

@@ -0,0 +1,42 @@
+const BASE = '/api'
+
+export async function fetchAllStatus() {
+  const res = await fetch(`${BASE}/status`)
+  if (!res.ok) throw new Error(`HTTP ${res.status}`)
+  return res.json()
+}
+
+export async function fetchLogs(vpsId, containerId, lines = 200) {
+  const res = await fetch(`${BASE}/vps/${vpsId}/containers/${containerId}/logs?lines=${lines}`)
+  if (!res.ok) throw new Error(`HTTP ${res.status}`)
+  return res.json()
+}
+
+export async function containerAction(vpsId, containerId, action) {
+  const res = await fetch(`${BASE}/vps/${vpsId}/containers/${containerId}/action`, {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify({ action }),
+  })
+  if (!res.ok) throw new Error(`HTTP ${res.status}`)
+  return res.json()
+}
+
+export async function addVps(data) {
+  const res = await fetch(`${BASE}/vps`, {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify(data),
+  })
+  if (!res.ok) {
+    const err = await res.json().catch(() => ({}))
+    throw new Error(err.detail ?? `HTTP ${res.status}`)
+  }
+  return res.json()
+}
+
+export async function deleteVps(vpsId) {
+  const res = await fetch(`${BASE}/vps/${vpsId}`, { method: 'DELETE' })
+  if (!res.ok) throw new Error(`HTTP ${res.status}`)
+  return res.json()
+}