add delta diff viewer for git

homes/modules/git.nix

@@ -3,14 +3,19 @@
   pkgs,
   ...
 }: {
-  programs.git = {
+  home.packages = with pkgs; [
+    delta # git diff viewer
+  ];
+
+  programs = {
+    git = {
       enable = true;
       lfs.enable = true;
 
       signing = {
-      # key = "F68745A836CA0412";
-      # format = "openpgp";
-      # signByDefault = true;
+        key = "F68745A836CA0412";
+        format = "openpgp";
+        signByDefault = true;
       };
 
       settings = {
@@ -29,6 +34,16 @@
         core.editor = "hx";
         github.user = "cry128";
 
+        # delta diff viewer
+        core.pager = "delta";
+        interactive.diffFilter = "delta --color-only";
+        delta = {
+          navigate = true;
+          line-numbers = true;
+          side-by-side = true;
+        };
+        merge.conflictStyle = "zdiff3";
+
         init = {
           defaultBranch = "main";
         };
@@ -71,4 +86,6 @@
         # }
       ];
     };
+
+  };
 }