chore(nix): bump nixpkgs 24.05 → 24.11

Three breakages handled:

- hardware.opengl → hardware.graphics (renamed in 24.11). Touches
  upboard.nix, douro.nix, batm3.nix, live.nix.
- vaapiIntel dropped — legacy pre-Broadwell driver, removed in
  nixpkgs. UP Board (Cherry Trail) and OptiPlex 9030 (Haswell) both
  use intel-media-driver, which stays.
- vaapiVdpau renamed → libva-vdpau-driver.

system.stateVersion stays 24.05 — convention is to never bump after
install. Existing Sintra and fresh flashes keep the 24.05 state
semantics; that's correct.

All 8 nixosConfigurations (4 models × {live,installed}) evaluate
clean with zero deprecation warnings on 24.11.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

flake.nix

@@ -3,7 +3,7 @@
 
   inputs = {
     # Stable NixOS for the ATM OS base
-    nixpkgs.url = "github:NixOS/nixpkgs/nixos-24.05";
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-24.11";
 
     # Unstable for Electron, Node.js, pnpm (latest versions)
     nixpkgs-unstable.url = "github:NixOS/nixpkgs/nixpkgs-unstable";