feat: server-side remote builder config (lazyworkhorse dispatches aarch64 to uConsole)

Server only — uConsole-side config will be added in uconsole-cm5-incremental branch.
Includes reusable module, builder system user, and SSH key placeholder.

flake.nix

@@ -102,9 +102,7 @@
               }
               nixos-raspberrypi.nixosModules.raspberry-pi-5.base
               nixos-uconsole.nixosModules.uconsole-cm5
-              ./modules/nixos/services/remote-builder.nix
               ./hosts/uConsole/configuration.nix
-              ./users/builder.nix
               ./hosts/uConsole/hardware-configuration.nix
             ];
           };

hosts/uConsole/configuration.nix

@@ -168,23 +168,4 @@
   # Reticulum uses its own encryption and doesn't need open ports
   # for basic mesh operations (peer-to-peer discovery).
   # For TCP interfaces, open additional ports as needed.
-
-  # ============================================================
-  # Remote builder — dispatches x86_64-linux builds to server
-  # ============================================================
-  services.remoteBuilder = {
-    enable = true;
-    machines = [
-      {
-        hostName = "lazyworkhorse.net";
-        port = 2424;
-        sshUser = "builder";
-        sshKey = "/etc/ssh/builder_key";
-        systems = [ "x86_64-linux" ];
-        maxJobs = 36;
-        supportedFeatures = [ "benchmark" "big-parallel" "nixos-test" ];
-      }
-    ];
-  };
-
 }