flake: extract devShell.nix and drop flake-compat shell.nix

flake.nix

@@ -3,17 +3,13 @@
     nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
     fenix.url = "github:nix-community/fenix";
     fenix.inputs.nixpkgs.follows = "nixpkgs";
-    llm-agents = {
-      url = "github:numtide/llm-agents.nix";
-      inputs.nixpkgs.follows = "nixpkgs";
-    };
     flake-compat = {
       url = "https://git.lix.systems/lix-project/flake-compat/archive/main.tar.gz";
       flake = false;
     };
   };
   outputs =
-    inputs@{ nixpkgs, fenix, ... }:
+    { nixpkgs, fenix, ... }:
     let
       forAllSystems = nixpkgs.lib.genAttrs nixpkgs.lib.systems.flakeExposed;
     in
@@ -24,37 +20,11 @@
           pkgs = import nixpkgs {
             inherit system;
             config.allowUnfree = true;
+            overlays = [ fenix.overlays.default ];
           };
-          llm-agents = inputs.llm-agents.packages.${pkgs.stdenv.hostPlatform.system};
         in
         {
-          default = pkgs.mkShell {
-            packages = with pkgs; [
-              (fenix.packages.${system}.latest.withComponents [
-                "cargo"
-                "clippy"
-                "rust-src"
-                "rustc"
-                "rustfmt"
-                "rust-analyzer"
-              ])
-              cargo-machete
-              cargo-bloat
-              lldb
-              valgrind
-              kdePackages.kcachegrind
-              hyperfine
-              just
-              samply
-              tokei
-              tombi
-
-              # llm-agents.codex
-              llm-agents.claude-code
-              llm-agents.opencode
-              # llm-agents.forge
-            ];
-          };
+          default = import ./devShell.nix { inherit pkgs; };
         }
       );
     };