Add per-VM autostart checkbox (single-select, persisted)

Only one VM can be marked for autostart at a time — checking a new
one unchecks the previous. Matched by host+vmid since the same vmid
can exist on multiple standalone Proxmox hosts in a cluster setup.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "proxmox-spice-client",
-  "version": "1.0.3",
+  "version": "1.0.4",
   "description": "VDI SPICE Client f\u00fcr Proxmox",
   "main": "src/main.js",
   "scripts": {