chore: update Dockerfile and rename build script for multi-architecture support

build-docker.sh

@@ -0,0 +1,32 @@
+#!/usr/bin/env bash
+# build.sh — Build Open Ticket Docker images for all supported architectures.
+#
+# Usage: ./build.sh <image> [--no-push]
+#   image   Full image name, e.g. djj123dj/open-ticket
+#
+# Example: ./build.sh djj123dj/open-ticket --no-push
+
+set -euo pipefail
+
+IMAGE="${1:?Usage: ./build.sh <image> [--no-push]}"
+PLATFORMS="linux/amd64,linux/arm/v6,linux/arm/v7,linux/arm64" # linux/s390x is taking too long to build, so we'll skip it for now
+VERSION=$(node -p "require('./package.json').version")
+
+# Create a multi-arch builder if it doesn't exist yet
+docker buildx inspect ot-builder &>/dev/null \
+    || docker buildx create --name ot-builder --driver docker-container --bootstrap --use
+docker buildx use ot-builder
+
+PUSH_FLAG="--push"
+[[ "${2:-}" == "--no-push" ]] && PUSH_FLAG=""
+
+docker buildx build \
+    --platform "$PLATFORMS" \
+    --tag "${IMAGE}:v${VERSION}" \
+    --tag "${IMAGE}:latest" \
+    $PUSH_FLAG \
+    .
+
+[[ -n "$PUSH_FLAG" ]] \
+    && echo "✓ Pushed ${IMAGE}:v${VERSION} and ${IMAGE}:latest" \
+    || echo "✓ Built ${IMAGE}:v${VERSION} (not pushed)"