fix: install Bun in Dockerfile (#284)

Install Bun in Dockerfile so `pnpm build` can run Bun scripts inside Docker.

Thanks @loukotal.

Dockerfile

@@ -1,5 +1,9 @@
 FROM node:22-bookworm
 
+# Install Bun (required for build scripts)
+RUN curl -fsSL https://bun.sh/install | bash
+ENV PATH="/root/.bun/bin:${PATH}"
+
 RUN corepack enable
 
 WORKDIR /app