git: ship difftastic as a standalone program

hosts/common/programs/assorted.nix

@@ -517,6 +517,8 @@ in
     # auth token, preferences
     delfin.persist.byStore.private = [ ".config/delfin" ];
 
+    difftastic.sandbox.autodetectCliPaths = "existing";
+
     dig.sandbox.net = "all";
 
     dmidecode.sandbox.extraPaths = [ "/sys/firmware/dmi" ];

hosts/common/programs/git.nix

@@ -19,6 +19,7 @@ in
       '';
     });
     suggestedPrograms = [
+      "difftastic"
       "ssh"
     ];
     sandbox.net = "clearnet";
@@ -57,7 +58,7 @@ in
       # - <https://difftastic.wilfred.me.uk/git.html>
       diff.tool = "difftastic";
       difftool.prompt = false;
-      "difftool \"difftastic\"".cmd = ''${lib.getExe pkgs.difftastic} "$LOCAL" "$REMOTE"'';
+      "difftool \"difftastic\"".cmd = ''difft "$LOCAL" "$REMOTE"'';
       # now run `git difftool` to use difftastic git
 
       # render dates as YYYY-MM-DD HH:MM:SS +TZ