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/claude/default.nix

@@ -1,20 +1,44 @@
-{ pkgs, inputs, ... }:
 {
-  home = {
-    packages = with pkgs; [
-      inputs.claude-code.packages.${pkgs.stdenv.hostPlatform.system}.default
+  config,
+  pkgs,
+  inputs,
+  lib,
+  ...
+}:
+let
+  # Official Anthropic Claude desktop app (Linux build, x86_64 only).
+  claude-desktop = pkgs.callPackage ../../../../pkgs/claude-desktop/package.nix {
+    inherit (config.custom.aiApps) deviceScaleFactor;
+  };
+in
+{
+  # Shared UI-scale knob for the Electron AI desktop apps (Claude Desktop, T3 Code).
+  # Set per-host (e.g. konishi's 4K@1x monitors want ~"1.5"); null = native scale.
+  options.custom.aiApps.deviceScaleFactor = lib.mkOption {
+    type = lib.types.nullOr lib.types.str;
+    default = null;
+    example = "1.5";
+    description = "--force-device-scale-factor value for Claude Desktop and T3 Code.";
+  };
 
-      # sandbox
-      bubblewrap
-      socat
-      libseccomp
+  config.home = {
+    packages =
+      with pkgs;
+      [
+        inputs.claude-code.packages.${pkgs.stdenv.hostPlatform.system}.default
 
-      # voice
-      sox
+        # sandbox
+        bubblewrap
+        socat
+        libseccomp
 
-      # beads
-      dolt
-    ];
+        # voice
+        sox
+
+        # beads
+        dolt
+      ]
+      ++ lib.optional pkgs.stdenv.hostPlatform.isx86_64 claude-desktop;
 
     file = {
       ".default-npm-packages".text = ''