Root cause of 'Connection closed' / VNCAuth failure:
- vncproxy was called without generate-password=1
- vnc_data.password was None → noVNC sent empty DES-encrypted challenge → Proxmox rejected
Fix:
- Add generate-password=1 to both qemu and lxc vncproxy requests
- If Proxmox returns password field (Proxmox 8.x VNCAuth): use it
- If not (Proxmox 9.x NoAuth): fall back to ticket as password
- Add diagnostic logging (password_len, has_generate_password)