fix: revert zellij-ps workaround, remove nixpkgs.config (useGlobalPkgs handles it)

profiles/base/default.nix

@@ -30,10 +30,9 @@
   ];
 
   # ── nixpkgs configuration ──
-  nixpkgs.config = {
-    allowUnfree = true;
-    allowUnfreePredicate = _: true;
-  };
+  # NOTE: When used via NixOS with useGlobalPkgs=true, nixpkgs.config is
+  # managed at the NixOS level. Only set it here for standalone HM usage.
+  # nixpkgs.config.allowUnfree = true;
 
   # ── Nix settings ──
   nix = {