manage global git config declaratively via programs.git.config

moves user identity and init.defaultBranch into /etc/gitconfig instead of stow-managed dotfiles. note: a per-user ~/.gitconfig still overrides these, so identity must stay out of the stow repo to avoid shadowing.

modules/features/git/default.nix

@@ -1,11 +1,23 @@
 {...}: {
-  # git user config (~/.config/git or ~/.gitconfig) is managed via stow.
-  # We only install git + related tooling and enable the gpg agent.
+  # Global git config lives in /etc/gitconfig via programs.git.config.
+  # Note: a per-user ~/.gitconfig (or ~/.config/git/config) overrides these,
+  # so keep identity out of the stow dotfiles to avoid shadowing this.
   flake.nixosModules.git = {pkgs, ...}: {
+    programs.git = {
+      enable = true;
+      config = {
+        user = {
+          name = "ahmza";
+          email = "hamza@ahmza.com";
+        };
+        init.defaultBranch = "main";
+      };
+    };
+
     environment.systemPackages = with pkgs; [
-      git
       git-secret
     ];
+
     programs.gnupg.agent = {
       enable = true;
       pinentryPackage = pkgs.pinentry-all;