Disable ai-usage providers via nix

modules/ai-usage.nix

@@ -5,6 +5,9 @@
     imports = [ ai-usage.homeManagerModules.default ];
     programs.ai-usage = {
       enable = true;
+      providers.cursor.enable = true;
+      providers.codex.enable = false;
+      providers.claude.enable = false;
       package = ai-usage.packages.${pkgs.stdenv.hostPlatform.system}.default;
     };
   };