feat: extract gaming config into dedicated gaming.nix module

Moves steam, gamemode, DualSense udev rules, and gaming packages
(lutris, winetricks, wine, dxvk, vkd3d-proton, mangohud, dualsensectl,
protonup-qt, prismlauncher) into gaming.nix. Also adds bluetooth/blueman
config to configuration.nix.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

configuration.nix

@@ -8,7 +8,8 @@
     ./niri.nix
     ./nvidia.nix
     ./shell.nix
-    ./yami-dev-stack.nix 
+    ./yami-dev-stack.nix
+    ./gaming.nix
   ];
 
   nix = {
@@ -58,6 +59,12 @@
     networkmanager.enable = true;
   };
 
+  hardware.bluetooth = {
+    enable = true;
+    powerOnBoot = true;
+  };
+  services.blueman.enable = true;
+
   time.timeZone = "Europe/Moscow";
 
   i18n = {
@@ -93,13 +100,6 @@
     tunMode.enable = true;
   };
 
-  programs.steam = {
-    enable = true;
-    remotePlay.openFirewall = true;
-    dedicatedServer.openFirewall = true;
-  };
-
-  programs.gamemode.enable = true;
 
   services.tailscale.enable = true;
   # Docker is now managed by yami-dev-stack.nix when that module is enabled.