Wizard environment discovery misses LXC containers; "VMID" labels should be VMID/CTID

[BrettVerney]

Bug: Discovery step only scans for VMs, not LXC containers

During the install wizard's Step 4 environment discovery, step4_run() (apps/wizard/views.py:256) calls api.get_vms(node_name) which queries the Proxmox /nodes/{node}/qemu endpoint only. LXC containers (/nodes/{node}/lxc) are never queried.

As a result:

• Existing container IDs are not collected into existing_vmids_json
• The VMID pool range configured in Step 5 can overlap with existing LXC CTIDs, leading to ID conflicts when ProxOrchestrator later provisions containers

Label issue: "VMID" terminology in the wizard excludes containers

Throughout the wizard steps and settings page, all labels, help text, and display strings refer only to "VMID" or "VMs". Since the ID pool is used for both QEMU VMs and LXC containers, these should read VMID/CTID or simply ID in the wizard context.

Affected locations:

File	Line(s)	Current text
templates/wizard/step4_results.html	119–120	"ProxOrchestrator will avoid these VMIDs when creating new VMs"
templates/wizard/step5.html	173, 179, 207	"VMID Pool Range", "Existing VMIDs on cluster", "auto-selects VMIDs…"
apps/wizard/forms.py	92–102, 128–129	"VMID Pool — Minimum/Maximum", validation messages
templates/wizard/step6.html	43	"VMID Pool" summary label
templates/wizard/settings.html	535, 558, 658–659	"VMID Pool Range", "creating VMs" help text

Note: The VMID/CTID distinction is appropriate within the main tool's VM and container sections — only the wizard's generic "pool" references need updating.

Fix scope

1. In step4_run(), also call the LXC list endpoint and merge container CTIDs into existing_vmids_json
2. Update wizard template labels/help text to say "VMID/CTID" or "ID" where the pool applies to both types