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/config/config.go

@@ -1,6 +1,7 @@
 package config
 
 import (
+	"database/sql"
 	"log"
 	"os"
 	"strconv"
@@ -47,6 +48,14 @@ func Load() *Config {
 	return cfg
 }
 
+func LoadPasswordFromDB(cfg *Config, db *sql.DB) {
+	var stored string
+	err := db.QueryRow(`SELECT value FROM settings WHERE key = 'admin_password'`).Scan(&stored)
+	if err == nil && stored != "" {
+		cfg.AdminPass = stored
+	}
+}
+
 func getEnv(key, defaultValue string) string {
 	if v := os.Getenv(key); v != "" {
 		return v