Consolidate Gitea runners on NixOS

Add the docker group to the runner services and allow passwordless
nixos-rebuild for the gitea-runner user.

nixos/hosts/mini-pc/default.nix

@@ -75,13 +75,27 @@
     }
   '';
 
-  services.gitea-actions-runner.instances."mini-pc-nixos" = {
+  services.gitea-actions-runner.instances."mini-pc" = {
     enable = true;
-    name = "mini-pc-nixos";
+    name = "mini-pc";
     url = "https://git.ada-dev.ru";
-    tokenFile = "/etc/gitea-runner/mini-pc-nixos.token";
-    labels = [ "mini-pc-nixos" ];
+    tokenFile = "/etc/gitea-runner/mini-pc.token";
+    labels = [ "mini-pc" "mini-pc-nixos" ];
   };
 
+  systemd.services."gitea-runner-mini-pc".serviceConfig.SupplementaryGroups = [ "docker" ];
+
+  security.sudo.extraRules = [
+    {
+      users = [ "gitea-runner" ];
+      commands = [
+        {
+          command = "/run/current-system/sw/bin/nixos-rebuild";
+          options = [ "NOPASSWD" ];
+        }
+      ];
+    }
+  ];
+
   system.stateVersion = "25.11";
 }