Consolidate docker checks

lib/message-helpers.sh

@@ -36,3 +36,24 @@ print_header() {
   echo -e "${BOLD}$1${NC}"
   echo -e "${BOLD}================================${NC}"
 }
+
+# Check Docker is available and running
+check_docker() {
+  if ! command -v docker &>/dev/null; then
+    print_error "Docker is not installed"
+    exit 1
+  fi
+
+  if ! docker info &>/dev/null; then
+    print_error "Docker daemon is not running"
+    print_warning "Start Docker with: sudo systemctl start docker"
+    exit 1
+  fi
+}
+
+# Build the Docker image if needed
+build_docker_image() {
+  local build_dir="$1"
+  print_info "Building Docker image..."
+  docker build -t omarchy-aur-builder:latest -f "$build_dir/Dockerfile" "$build_dir"
+}