Set up core flake.nix file.

flake.nix

@@ -1,8 +1,71 @@
 {
-  description = "Metanix infrastructure logic library";
+  description = "Metanix core flake (meta.nix-driven outputs)";
 
-  outputs = { self, nixpkgs }: {
+  inputs = {
-    lib = { data, lib }:
+    # Base system
-      import ./lib/metanix.nix { inherit data lib; };
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+
+    # Tooling we integrate with
+    deploy-rs.url = "github:serokell/deploy-rs";
+    disko.url     = "github:nix-community/disko";
   };
+
+  outputs = { self, nixpkgs, deploy-rs, disko, ... }:
+  let
+    lib = nixpkgs.lib;
+
+    systems = [ "x86_64-linux" "aarch64-linux" ];
+
+    forAllSystems = f:
+      lib.genAttrs systems (system: f {
+        inherit system;
+        pkgs = import nixpkgs { inherit system; };
+      });
+
+    metanixLib = import ./lib {
+      inherit nixpkgs deploy-rs disko;
+    };
+
+    # Build the "world" view from meta.nix
+    world = metanixLib.fromMeta {
+      metaFile  = ./meta.nix;
+      inherit nixpkgs deploy-rs disko;
+    };
+
+  in
+  {
+
+    # So other flakes *can* depend on Metanix as a library if needed.
+    lib = metanixLib;
+
+    # For nixos-rebuild / nixos-anywhere / deploy-rs
+    nixosConfigurations = world.nixosConfigurations;
+
+    # For deploy-rs
+    deploy = {
+      nodes = world.deployNodes;
+    };
+
+    # For disko-based installs (either as bare configs or modules)
+    diskoConfigurations = world.diskoConfigurations;
+
+    checks = forAllSystems ({ pkgs, ... }: {
+      meta-validate = metanixLib.checkMeta {
+        inherit pkgs;
+        metaFile = ./meta.nix;
+      };
+    });
+
+    devShells = forAllSystems ({ system, pkgs }: {
+      default = pkgs.mkShell {
+        name = "metanix-dev";
+        buildInputs = [
+          pkgs.nix
+          pkgs.git
+          deploy-rs.packages.${system}.default
+          disko.packages.${system}.default
+        ];
+      };
+    });
+  }
 }