feat: create initial home manager modules

modules/home-manager/dev.nix

@@ -0,0 +1,37 @@
+{
+  config,
+  lib,
+  pkgs,
+  inputs,
+  ...
+}:
+let
+  packages = inputs.self.outputs.packages.${pkgs.stdenv.hostPlatform.system};
+in
+{
+  options = {
+    dev.enable = lib.mkEnableOption "development tools";
+  };
+
+  config = lib.mkIf config.dev.enable {
+    home.packages = [
+      pkgs.git
+      packages.git-linearize
+      packages.ggman
+      pkgs.go
+      pkgs.python3
+      pkgs.mdbook
+      pkgs.marksman
+      pkgs.mdformat
+      pkgs.google-cloud-sdk
+      pkgs.google-cloud-sql-proxy
+      packages.ahab
+      pkgs.just
+    ];
+
+    programs.direnv = {
+      enable = true;
+      nix-direnv.enable = true;
+    };
+  };
+}