Add Steam and Vencord configurations: include desktop entries, session variables, and system packages

home/programs/steam/default.nix

@@ -0,0 +1,28 @@
+{
+  pkgs,
+  ...
+}: {
+  home.packages = with pkgs; [
+    steam
+    protonup-ng
+    proton-ge-bin
+  ];
+
+  xdg.desktopEntries = {
+    Steam = {
+      name = "Steam";
+      exec = "${pkgs.steam}/bin/steam";
+      icon = "steam";
+      type = "Application";
+      categories = [
+        "Game"
+        "Network"
+      ];
+      terminal = false;
+    };
+  };
+
+  home.sessionVariables = {
+    STEAM_FORCE_DESKTOPUI_SCALING = "1.25";
+  };
+}

home/programs/steam/system.nix

@@ -0,0 +1,13 @@
+{ ... }: {
+  # Steam runtime tweaks (user-session level, not NixOS system config)
+
+  home.sessionVariables = {
+    # Improves scaling consistency on HiDPI / Wayland setups
+    STEAM_FORCE_DESKTOPUI_SCALING = "1.25";
+
+    # Optional Proton-related behavior toggles (safe defaults)
+    PROTON_ENABLE_NVAPI = "1";
+    PROTON_NO_ESYNC = "0";
+    PROTON_NO_FSYNC = "0";
+  };
+}