added qr code

modules/core/sovran-hub.nix

@@ -227,6 +227,9 @@ in
         StandardOutput = "journal";
         StandardError  = "journal";
       };
+
+      # ── Make qrencode available for QR code generation ────────
+      path = [ pkgs.qrencode ];
     };
 
     # ── System update as a detached oneshot ─────────────────────
@@ -241,4 +244,4 @@ in
     # ── Open firewall port ─────────────────────────────────────
     networking.firewall.allowedTCPPorts = [ 8937 ];
   };
-}
+}