feat: add uConsole CM5 host configuration

- Add nixos-uconsole and nixos-hardware inputs for CM5/RPi5 support
- Create hosts/uconsole/configuration.nix with HAM radio, SDR, and security tools
- Create hosts/uconsole/hardware-configuration.nix for CM5 hardware
- Register uConsole in flake.nix nixosConfigurations
- Add uconsole host key placeholder to lib/keys.nix

flake.nix

@@ -12,6 +12,10 @@
       url = "git+https://git.lix.systems/lix-project/lix?ref=main";
       inputs.nixpkgs.follows = "nixpkgs";
     };
+    # uConsole CM5 hardware support
+    nixos-uconsole.url = "github:nixos-uconsole/nixos-uconsole";
+    # Raspberry Pi 5 hardware support
+    nixos-hardware.url = "github:nixos/nixos-hardware/master";
     self.submodules = true;
   };
 
@@ -79,6 +83,20 @@
               ./hosts/cyt-pi/hardware-configuration.nix
             ];
           };
+
+          uConsole = nixpkgs.lib.nixosSystem {
+            specialArgs = { inherit self keys paths inputs; };
+            modules = [
+              {
+                nixpkgs.overlays = overlays;
+                nixpkgs.config.allowUnfree = true;
+                nixpkgs.hostPlatform = "aarch64-linux";
+                nix.package = lix.packages."aarch64-linux".default;
+              }
+              ./hosts/uconsole/configuration.nix
+              ./hosts/uconsole/hardware-configuration.nix
+            ];
+          };
         };
         devShells.${system}.default = devShell;
       };