feat(home): package Claude Desktop and T3 Code, with per-host UI scaling

Add two Electron AI desktop apps built from their official upstream
binaries and wire them into the home config (x86_64 only):

- claude-desktop: Anthropic's official Linux .deb, unpacked via dpkg +
  autoPatchelfHook. Wrapper disables the SUID sandbox (nix store can't
  set it up) and adds the NixOS GL driver path so it hardware-accelerates
  instead of falling back to software rendering.
- t3-code: pingdotgg/t3code AppImage via appimageTools.wrapType2, with
  desktop entry + hicolor icons.

Both share a new custom.aiApps.deviceScaleFactor option feeding
--force-device-scale-factor; konishi's 4K@1x monitors set it to "1.5",
arrakis stays native.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

home/common/programs/t3-code.nix

@@ -0,0 +1,16 @@
+{
+  config,
+  pkgs,
+  lib,
+  ...
+}:
+let
+  # T3 Code: open-source desktop control plane for coding agents (x86_64 only).
+  # Shares the custom.aiApps.deviceScaleFactor knob (defined in ../claude).
+  t3-code = pkgs.callPackage ../../../pkgs/t3-code/package.nix {
+    inherit (config.custom.aiApps) deviceScaleFactor;
+  };
+in
+{
+  home.packages = lib.optional pkgs.stdenv.hostPlatform.isx86_64 t3-code;
+}