A new <select> element above the VLAN ID input lets users pick an
existing VLAN by name instead of typing the ID. Options are loaded
from /vlanlist on page load and re-loaded after successful
Update/Create operations.
Selection triggers the existing fetchVLAN() flow.
Falls back gracefully if /vlanlist returns an empty list or fails:
the dropdown is hidden and the existing ID input remains functional.
Erdnusschokolade
defb37c06a
