Add mcrcon-rbw wrapper for Minecraft RCON

Wrapper that auto-authenticates via rbw (Bitwarden) for RCON access.
- Uses minecraft-rcon entry from Bitwarden
- Defaults to 10.0.0.165:25575 (LoadBalancer IP)
- Supports MCRCON_HOST/PORT overrides
- Interactive terminal mode when no args provided

Part of k3s-cluster-config bead k3s-cluster-config-byg

packages/mcrcon-rbw/default.nix

@@ -0,0 +1,40 @@
+{ pkgs, ... }:
+
+pkgs.writeShellScriptBin "mcrcon" ''
+  set -euo pipefail
+
+  # Configuration - can be overridden with environment variables
+  MINECRAFT_RCON_HOST="''${MCRCON_HOST:-10.0.0.165}"
+  MINECRAFT_RCON_PORT="''${MCRCON_PORT:-25575}"
+  RBW_ENTRY="minecraft-rcon"
+
+  # Check if rbw is available
+  if ! command -v rbw &> /dev/null; then
+    echo "Error: rbw is not available. Please ensure rbw is installed and configured."
+    exit 1
+  fi
+
+  # Retrieve password from Bitwarden
+  if ! MCRCON_PASS=$(rbw get "$RBW_ENTRY" 2>/dev/null); then
+    echo "Error: Failed to retrieve RCON password from rbw entry '$RBW_ENTRY'"
+    echo "Please ensure the entry exists in Bitwarden and rbw is synced."
+    echo ""
+    echo "To create the entry:"
+    echo "  1. Add 'minecraft-rcon' to Bitwarden with the RCON password"
+    echo "  2. Run 'rbw sync' to refresh the local cache"
+    exit 1
+  fi
+
+  # Export for mcrcon
+  export MCRCON_HOST="$MINECRAFT_RCON_HOST"
+  export MCRCON_PORT="$MINECRAFT_RCON_PORT"
+  export MCRCON_PASS
+
+  # If no arguments provided, start interactive terminal mode
+  if [[ $# -eq 0 ]]; then
+    exec ${pkgs.mcrcon}/bin/mcrcon -t
+  fi
+
+  # Execute mcrcon with all provided arguments
+  exec ${pkgs.mcrcon}/bin/mcrcon "$@"
+''