Fix create-proxmox-resource.sh defaulting hostname to the flake target

--name (used as pct/qm create's --hostname/--name) defaulted to
$flake_target (e.g. "lxc-nix-cache"), not $host (e.g. "nix-cache"). Since
proxmoxLXC.manageHostName pulls the guest's real networking.hostName
straight from Proxmox's own container config, this silently overrode
host.nix's hostName with a build-type-specific name. Default --name to
--host instead, so the guest's identity matches host.nix regardless of
which platform variant built it.

Found by spinning up a fresh lxc-nix-cache test container and noticing its
hostname was "lxc-nix-cache" instead of "nix-cache".

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

scripts/create-proxmox-resource.sh

@@ -40,8 +40,12 @@ Create mode (default):
                         config.networking.hostName (server, docker,
                         nix-cache, nixos, pxe-boot, nix-minimal). Use
                         --list to see what's available for --type.
-  --name <name>          Proxmox display name/hostname (default: the flake
-                          target name, e.g. lxc-server)
+  --name <name>          Proxmox display name/hostname (default: --host's
+                          value, e.g. nix-cache -- for lxc this becomes the
+                          guest's real networking.hostName too, since
+                          proxmoxLXC.manageHostName pulls it from Proxmox's
+                          own container config, so it must match host.nix
+                          regardless of build type)
   --vmid <n>              Numeric VMID (default: next free, via
                           \`pvesh get /cluster/nextid\` on the node).
                           Refuses to run if this ID already exists.
@@ -274,7 +278,13 @@ if [[ -z "$flake_target" ]]; then
   exit 1
 fi
 
-[[ -z "$name" ]] && name="$flake_target"
+# The container/VM's real identity is --host (e.g. "nix-cache"), validated
+# above against config.networking.hostName -- not the flake target name
+# (e.g. "lxc-nix-cache"), which is build-type-specific and only exists to
+# pick which platform variant to build. Defaulting --name to the flake
+# target would make lxc's --hostname (which proxmoxLXC.manageHostName
+# feeds straight into the guest's real hostname) disagree with host.nix.
+[[ -z "$name" ]] && name="$host"
 
 # --- refuse to duplicate a host that's already really deployed ----------
 # Checked by hostName, not exact flake target: proxmox-server being