Fix venv derivation - define in let block properly

modules/python-environment.nix

@@ -8,6 +8,17 @@ let
   cfg = config.programs.dots-hyprland.python;
   mainCfg = config.programs.dots-hyprland;
   
+  # Build Python venv as a derivation (happens during build, not activation)
+  venvDerivation = pkgs.runCommand "dots-hyprland-venv" {
+    buildInputs = [ pkgs.python312 ];
+    nativeBuildInputs = with pkgs; [ cmake pkg-config gcc gnumake wayland wayland-protocols ];
+  } ''
+    export HOME=$TMPDIR
+    mkdir -p $out
+    ${setupVenvScript}
+    mv $HOME/.local/state/quickshell/.venv $out/venv
+  '';
+  
   # Virtual environment setup script that replicates installer behavior
   setupVenvScript = pkgs.writeShellScript "setup-dots-hyprland-venv" ''
     #!/usr/bin/env bash
@@ -228,15 +239,7 @@ in
         echo "🔗 Linking pre-built Python venv..."
         $DRY_RUN_CMD mkdir -p $(dirname ${cfg.venvPath})
         $DRY_RUN_CMD rm -rf ${cfg.venvPath}
-        $DRY_RUN_CMD cp -r ${pkgs.runCommand "dots-hyprland-venv" {
-          buildInputs = [ pkgs.python312 ];
-          nativeBuildInputs = with pkgs; [ cmake pkg-config gcc gnumake wayland wayland-protocols ];
-        } ''
-          export HOME=$TMPDIR
-          mkdir -p $out
-          ${setupVenvScript}
-          mv $HOME/.local/state/quickshell/.venv $out/venv
-        ''}/venv ${cfg.venvPath}
+        $DRY_RUN_CMD cp -r ${venvDerivation}/venv ${cfg.venvPath}
         echo "✅ Python venv linked successfully"
       ''
     );