fix(scripts): add missing build-docker-express.sh script

Ticket: BTC-2566

- Create executable build-docker-express.sh script with proper content

Author: andyyan162

scripts/build-docker-express.sh

@@ -0,0 +1,31 @@
+#!/bin/bash
+
+# Build Docker Express script
+# This script builds the BitGo Express Docker image
+
+set -e
+
+echo "Building Docker Express image..."
+
+# Update dockerfile first
+yarn update-dockerfile
+
+# Build Docker image using podman (or docker if podman not available)
+if command -v podman &> /dev/null; then
+    echo "Using podman to build image..."
+    podman build --platform=linux/amd64 \
+        -t bitgo/express:latest \
+        -t bitgo/express:$(jq -r .version < modules/express/package.json) \
+        .
+elif command -v docker &> /dev/null; then
+    echo "Using docker to build image..."
+    docker build --platform=linux/amd64 \
+        -t bitgo/express:latest \
+        -t bitgo/express:$(jq -r .version < modules/express/package.json) \
+        .
+else
+    echo "Error: Neither podman nor docker is available"
+    exit 1
+fi
+
+echo "Docker Express image built successfully!"