feat: add hub-managed Wallet Connections scaffolding

modules/core/sovran-hub.nix

@@ -61,6 +61,9 @@ let
         { label = "Server"; value = "tcp://127.0.0.1:50001 (Electrs)"; }
         { label = "Status"; value = "Auto-configured on first boot"; }
       ]; }
+      { name = "Wallet Connections"; unit = "nwc-wallets.service"; type = "system"; icon = "zeus"; enabled = cfg.features."nwc-wallets"; category = "bitcoin-apps"; credentials = [
+        { label = "Lightning Address Domain"; file = "/var/lib/domains/lightning"; }
+      ]; }
       { name = "Mempool";            unit = "mempool.service";      type = "system"; icon = "mempool";      enabled = cfg.features.mempool;  category = "bitcoin-apps"; credentials = [
         { label = "Tor Address — Access from anywhere via Tor Browser"; file = "/var/lib/tor/onion/mempool-frontend/hostname"; prefix = "http://"; }
         { label = "Local Network — Access on your home network only"; file = "/var/lib/secrets/internal-ip"; prefix = "http://"; suffix = ":60847"; }
@@ -353,6 +356,16 @@ uvicorn.run(
 LAUNCHER
       chmod +x $out/bin/sovran-hub-web
 
+      cat > $out/bin/nwc-wallet <<LAUNCHER
+#!${pkgs.python3}/bin/python3
+import os, sys
+base = os.path.join("$out", "lib", "sovran-hub-web")
+sys.path.insert(0, base)
+from sovran_systemsos_web.nwc_wallet_cli import main
+sys.exit(main())
+LAUNCHER
+      chmod +x $out/bin/nwc-wallet
+
       runHook postInstall
     '';