Refactor git modules

modules/git.nix

@@ -1,63 +0,0 @@
-{ config, pkgs, ... }:
-
-{
-  programs.git-credential-oauth = {
-    enable = true;
-  };
-
-  programs.git = {
-    enable = true;
-
-    ignores = [
-      "**/.claude/settings.local.json"
-      ".DS_Store"
-      ".env"
-      "node_modules/"
-      ".venv/"
-    ];
-
-    settings = {
-      user = {
-        name = "Yan Lin";
-        email = "github@yanlincs.com";
-      };
-
-      credential = {
-        "https://github.com".helper = "oauth";
-        "https://gitlab.com".helper = "oauth";
-        "https://bitbucket.org".helper = "oauth";
-        "https://git.overleaf.com".helper = "store";
-        "https://git.overleaf.com".username = "git";
-      };
-
-      core = {
-        editor = "nvim";
-        autocrlf = "input";
-        ignorecase = false;
-      };
-
-      init.defaultBranch = "main";
-
-      push = {
-        default = "simple";
-        autoSetupRemote = true;
-      };
-
-      pull = {
-        rebase = true;
-      };
-
-      merge = {
-        conflictstyle = "diff3";
-      };
-
-      diff = {
-        colorMoved = "default";
-      };
-
-      status = {
-        showUntrackedFiles = "all";
-      };
-    };
-  };
-}