feat: refactor sgclaw around zeroclaw compat runtime

third_party/zeroclaw/flake.nix

@@ -0,0 +1,61 @@
+{
+  inputs = {
+    flake-utils.url = "github:numtide/flake-utils";
+    fenix = {
+      url = "github:nix-community/fenix";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+    nixpkgs.url = "nixpkgs/nixos-unstable";
+  };
+
+  outputs = { flake-utils, fenix, nixpkgs, ... }:
+    let
+      nixosModule = { pkgs, ... }: {
+        nixpkgs.overlays = [ fenix.overlays.default ];
+        environment.systemPackages = [
+          (pkgs.fenix.stable.withComponents [
+            "cargo"
+            "clippy"
+            "rust-src"
+            "rustc"
+            "rustfmt"
+          ])
+          pkgs.rust-analyzer
+        ];
+      };
+    in
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = import nixpkgs {
+          inherit system;
+          overlays = [ fenix.overlays.default ];
+        };
+        rustToolchain = pkgs.fenix.stable.withComponents [
+          "cargo"
+          "clippy"
+          "rust-src"
+          "rustc"
+          "rustfmt"
+        ];
+      in {
+        packages.default = fenix.packages.${system}.stable.toolchain;
+        devShells.default = pkgs.mkShell {
+          packages = [
+            rustToolchain
+            pkgs.rust-analyzer
+          ];
+        };
+      }) // {
+      nixosConfigurations = {
+        nixos = nixpkgs.lib.nixosSystem {
+          system = "x86_64-linux";
+          modules = [ nixosModule ];
+        };
+
+        nixos-aarch64 = nixpkgs.lib.nixosSystem {
+          system = "aarch64-linux";
+          modules = [ nixosModule ];
+        };
+      };
+    };
+}