chore(docker): ensure resilient multi-arch detection and explicit ziglang dependency

Dockerfile

@@ -18,11 +18,11 @@ ARG TARGETARCH
 # zig (via the cargo-zigbuild wheel) is the cross C toolchain for musl targets.
 RUN apt-get update && apt-get install -y --no-install-recommends python3-pip \
  && rm -rf /var/lib/apt/lists/* \
- && pip install --no-cache-dir --break-system-packages cargo-zigbuild
+ && pip install --no-cache-dir --break-system-packages cargo-zigbuild ziglang
-RUN case "$TARGETARCH" in \
+RUN case "${TARGETARCH:-$(uname -m)}" in \
-      amd64) echo x86_64-unknown-linux-musl ;; \
+      amd64|x86_64) echo x86_64-unknown-linux-musl ;; \
-      arm64) echo aarch64-unknown-linux-musl ;; \
+      arm64|aarch64) echo aarch64-unknown-linux-musl ;; \
-      *) echo "unsupported arch $TARGETARCH" >&2; exit 1 ;; \
+      *) echo "unsupported arch ${TARGETARCH:-$(uname -m)}" >&2; exit 1 ;; \
     esac > /rust-target \
  && rustup target add "$(cat /rust-target)"
 WORKDIR /src

docker-compose.yml

@@ -1,7 +1,7 @@
 # SCOPENET admin panel
 #
 #   cp .env.example .env    # set ADMIN_PASSWORD at least
-#   docker compose up -d
+#   docker compose up -d --build
 #
 # Then open http://localhost:8080 (or your domain behind a reverse proxy).
 services: