chore: upgrade nixpkgs/home-manager to 26.05 and re-lock

- nixpkgs: nixos-25.05 -> nixos-26.05 (rev 70cc4559)
- home-manager: release-25.05 -> release-26.05
- fix 26.05 breaking changes: fcitx5-configtool/fcitx5-chinese-addons rename,
  resolved.extraConfig -> settings.Resolve, amdvlk removed (RADV default),
  desktop: import missing hardware-configuration.nix
- home/git.nix: migrate deprecated userName/extraConfig to settings

home/git.nix

@@ -2,9 +2,9 @@
 {
   programs.git = {
     enable = true;
-    userName = "luochen570";
-    userEmail = "1160510664@qq.com";
-    extraConfig = {
+    settings = {
+      user.name = "luochen570";
+      user.email = "1160510664@qq.com";
       init.defaultBranch = "main";
     };
   };