fix(grid-rs): pull wgrib2 from the Elixir image

wgrib2 isn't in Debian apt on trixie — the main prop Dockerfile builds
it from source in a dedicated stage. Rather than duplicate that 5-min
compile in the Rust image's CI path, copy the already-built
/usr/local/bin/wgrib2 + /usr/local/lib/libg2c.so* out of the published
Elixir image.

Also add the libgfortran5/libaec0/zlib1g/libpng16-16t64/libopenjp2-7
runtime deps that wgrib2 links dynamically against — same set the
Elixir runtime installs.

rust/prop_grid_rs/Dockerfile

@@ -1,8 +1,15 @@
 # syntax=docker/dockerfile:1.7
 #
-# Multi-arch build for `prop-grid-rs`. wgrib2 is installed from Debian
-# Trixie (same version the Elixir image uses). The binary runs as a
-# non-root uid that matches the fsGroup on the NFS scores mount.
+# Multi-arch build for `prop-grid-rs`. wgrib2 isn't in Debian apt — the
+# Elixir image builds it from source in its own stage. Rather than
+# rebuild it here (~5 min per CI run), copy the binary + libg2c out of
+# the already-published Elixir image.
+#
+# Runtime uid 65534 matches the fsGroup on the NFS scores mount.
+ARG WGRIB2_IMAGE=git.mcintire.me/graham/prop:main
+
+FROM ${WGRIB2_IMAGE} AS wgrib2-src
+
 FROM rust:1.94-trixie AS builder
 WORKDIR /src
 
@@ -25,15 +32,24 @@ RUN rustup component add clippy \
  && cargo test --release \
  && cargo build --release --bin worker
 
-# Runtime image: slim debian plus wgrib2. libexpat/libjasper pulled in
-# transitively by wgrib2 for PNG/JPEG2000 GRIB2 decompression.
+# Runtime image: slim debian + the shared libs wgrib2 links against.
+# libgfortran5/libaec0/zlib1g/libpng16-16t64/libopenjp2-7 mirror the
+# Elixir runtime stage.
 FROM debian:trixie-slim AS runtime
 RUN apt-get update && apt-get install -y --no-install-recommends \
-      wgrib2 \
       ca-certificates \
       tini \
+      libgfortran5 \
+      libaec0 \
+      zlib1g \
+      libpng16-16t64 \
+      libopenjp2-7 \
  && rm -rf /var/lib/apt/lists/*
 
+COPY --from=wgrib2-src /usr/local/bin/wgrib2 /usr/local/bin/wgrib2
+COPY --from=wgrib2-src /usr/local/lib/libg2c.so* /usr/local/lib/
+RUN ldconfig
+
 COPY --from=builder /src/target/release/worker /usr/local/bin/prop-grid-rs
 
 USER 65534:65534