refactor: use terminal package attr paths with shared resolver

modules/lib.nix

@@ -56,6 +56,13 @@ let
           '';
     };
 
+  resolvePackagePath =
+    {
+      pkgs,
+      path,
+    }:
+    lib.attrByPath path null pkgs;
+
   mkHostUser =
     {
       account,
@@ -136,6 +143,13 @@ in
     readOnly = true;
   };
 
+  options.meta.lib.resolvePackagePath = lib.mkOption {
+    type = lib.types.raw;
+    description = "Internal helper to resolve package attr paths against the local pkgs set.";
+    internal = true;
+    readOnly = true;
+  };
+
   options.meta.lib.users = lib.mkOption {
     type = lib.types.attrs;
     description = "Canonical user attrsets shared by host definitions.";
@@ -148,6 +162,7 @@ in
       mkCaddyReverseProxy
       mkHost
       mkHostUser
+      resolvePackagePath
       ;
   };
 }