feat: merge PVE VM management + local features

- Merge PVE (Proxmox VE) virtual machine management from remote
  - PVE host CRUD API
  - VM status query / start / stop operations
  - PVE database tables and models
  - Frontend VM status display and control buttons
  - SPA routing fix for nested asset paths

- Keep local features:
  - Change password functionality
  - Log cleanup service
  - Docker containerization (Dockerfile + docker-compose)
  - Empty machine ping log spam fix
  - settings table for admin password storage

- Update machines handlers to support PVE fields
- Update frontend API client with PVE endpoints

server/models/models.go

@@ -58,6 +58,10 @@ type Machine struct {
 	TotalOfflineSeconds   int        `json:"total_offline_seconds"`
 	LastOfflineAt         *time.Time `json:"last_offline_at"`
 	LastOfflineReason     NullString `json:"last_offline_reason"`
+	// PVE 相关字段
+	PVEHostID    *int64     `json:"pve_host_id"`
+	PVEVMID      NullString `json:"pve_vmid"`
+	PVEVMStatus  string     `json:"pve_vm_status"` // "running", "stopped", ""
 }
 
 type OfflineLog struct {
@@ -108,6 +112,11 @@ type LoginRequest struct {
 	Password string `json:"password" binding:"required"`
 }
 
+type ChangePasswordRequest struct {
+	OldPassword string `json:"old_password" binding:"required"`
+	NewPassword string `json:"new_password" binding:"required,min=6"`
+}
+
 type SSHInfoRequest struct {
 	Username string `json:"username" binding:"required"`
 	Password string `json:"password"`
@@ -125,3 +134,26 @@ type SSHInfoResult struct {
 	RawMemoryInfo string   `json:"raw_memory_info"`
 	RawDiskInfo   string   `json:"raw_disk_info"`
 }
+
+type PVEHost struct {
+	ID         int64     `json:"id"`
+	Name       string    `json:"name"`
+	Hostname   string    `json:"hostname"`
+	Port       int       `json:"port"`
+	Username   string    `json:"username"`
+	PasswordEnc string   `json:"password_enc"`
+	NodeName   string    `json:"node_name"`
+	VerifySSL  bool      `json:"verify_ssl"`
+	CreatedAt  time.Time `json:"created_at"`
+	UpdatedAt  time.Time `json:"updated_at"`
+	// 运行时使用，不存储
+	Password   string    `json:"password"`
+}
+
+type PVEVMStatus struct {
+	Status     string   `json:"status"` // "running", "stopped"
+	Uptime     int64    `json:"uptime"`
+	CPU        float64  `json:"cpu"`
+	MemoryUsed int64    `json:"memory_used"`
+	MemoryTotal int64   `json:"memory_total"`
+}