feat: move distribution builds to platform Docker builder

platform/distribution-builder/Dockerfile

@@ -0,0 +1,11 @@
+# syntax=docker/dockerfile:1
+
+FROM golang:1.25.1-bookworm
+
+RUN apt-get update \
+    && apt-get install -y --no-install-recommends ca-certificates git \
+    && rm -rf /var/lib/apt/lists/* \
+    && go version \
+    && git --version
+
+WORKDIR /workspace