ci: add container build workflow

Add prebuilt build images and a publish workflow to speed CI by reusing heavy dependencies.

packages/containers/base/Dockerfile

@@ -0,0 +1,18 @@
+FROM ubuntu:24.04
+
+ARG DEBIAN_FRONTEND=noninteractive
+
+RUN apt-get update \
+  && apt-get install -y --no-install-recommends \
+    build-essential \
+    ca-certificates \
+    curl \
+    git \
+    jq \
+    openssh-client \
+    pkg-config \
+    python3 \
+    unzip \
+    xz-utils \
+    zip \
+  && rm -rf /var/lib/apt/lists/*