feat: Add nvidia compatibility option for LXC devices

docs/INVENTORY.md

@@ -343,6 +343,34 @@ nix-lxc = {
 };
 ```
 
+### Proxmox LXC with NVIDIA (Dual P40 Example)
+
+```nix
+nix-lxc = {
+  devices = {
+    "gpu-builder" = {
+      athenix.host.useHostPrefix = false;
+      athenix.sw.type = "headless";
+
+      # Optional NVIDIA containerization support
+      athenix.hw.nix-lxc.cuda = {
+        enable = true;
+        # Expose both GPUs (index-based)
+        visibleDevices = [ "0" "1" ];
+        # Select a compatible driver branch for older cards when needed
+        driver.channel = "legacy_470";
+        driverCapabilities = [ "compute" "utility" ];
+      };
+    };
+  };
+};
+```
+
+Notes:
+- Proxmox host must provide `/dev/nvidia*` devices to the container.
+- Use `driver.channel = "dc_550"` (default) for newer datacenter cards when supported.
+- Use `driver.package` only when you need an explicit package override.
+
 ### WSL Instances
 
 ```nix