nix: remove flake; use nix2 shell

default.nix

@@ -1,8 +0,0 @@
-{rustPlatform}:
-rustPlatform.buildRustPackage {
-  pname = "sample-rust";
-  version = "0.0.1";
-
-  src = ./.;
-  cargoLock.lockFile = ./Cargo.lock;
-}

flake.lock

@@ -1,26 +0,0 @@
-{
-  "nodes": {
-    "nixpkgs": {
-      "locked": {
-        "lastModified": 1733039856,
-        "narHash": "sha256-CAvvt3N7MWFlEpspYtfth5jWzbHQUAUOufOVXgm03rw=",
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "0a644d62935fd8c0e6d9244c2ee2e8f6c2b6158c",
-        "type": "github"
-      },
-      "original": {
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "type": "github"
-      }
-    },
-    "root": {
-      "inputs": {
-        "nixpkgs": "nixpkgs"
-      }
-    }
-  },
-  "root": "root",
-  "version": 7
-}

flake.nix

@@ -1,24 +0,0 @@
-{
-  description = "Rust Project Template";
-  inputs.nixpkgs.url = "github:NixOS/nixpkgs";
-
-  outputs = {
-    self,
-    nixpkgs,
-  }: let
-    systems = ["x86_64-linux" "aarch64-linux"];
-    forEachSystem = nixpkgs.lib.genAttrs systems;
-
-    pkgsForEach = nixpkgs.legacyPackages;
-  in rec {
-    packages = forEachSystem (system: {
-      default = pkgsForEach.${system}.callPackage ./default.nix {};
-    });
-
-    devShells = forEachSystem (system: {
-      default = pkgsForEach.${system}.callPackage ./shell.nix {};
-    });
-
-    hydraJobs = packages;
-  };
-}

shell.nix

@@ -1,20 +1,10 @@
-{
-  callPackage,
-  rust-analyzer,
-  rustfmt,
-  clippy,
-  cargo,
-}: let
-  mainPkg = callPackage ./default.nix {};
-in
-  mainPkg.overrideAttrs (oa: {
-    nativeBuildInputs =
-      [
-        # Additional rust tooling
-        rust-analyzer
-        rustfmt
-        clippy
-        cargo
-      ]
-      ++ (oa.nativeBuildInputs or []);
-  })
+{pkgs ? import <nixpkgs> {}, ...}:
+pkgs.mkShell {
+  name = "frzndev";
+  packages = with pkgs; [
+    rust-analyzer
+    rustfmt
+    clippy
+    cargo
+  ];
+}