chore(sterni/code.sterni.lv): deny indexing

All repositories under code.sterni.lv are mirrors, so there's no value
in AI startups endlessly crawling the nixpkgs git history on
code.sterni.lv…

Change-Id: Iaac296315f325ced3cfd0852ae1d8d3f3815ea5b
Reviewed-on: https://cl.tvl.fyi/c/depot/+/12803
Reviewed-by: sterni <sternenseemann@systemli.org>
Autosubmit: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI

users/sterni/machines/ingeborg/http/code.sterni.lv.nix

@@ -118,6 +118,8 @@ let
     enable-blame=1
     enable-commit-graph=1
 
+    robots=noindex,nofollow
+
     root-title=code.sterni.lv
     root-desc=
     css=/cgit.css
@@ -191,6 +193,12 @@ in
       extraConfig = ''
         try_files $uri @cgit;
 
+        # Note this overrides the default robots.txt cgit-pink ships
+        location = /robots.txt {
+           add_header Content-Type text/plain;
+           return 200 "User-agent: *\nDisallow: /\n";
+        }
+
         location @cgit {
           include ${pkgs.nginx}/conf/fastcgi_params;
           fastcgi_param    SCRIPT_FILENAME ${pkgs.cgit-pink}/cgit/cgit.cgi;