Linux: RUNPATH guard, packaging in the container on CI, source archives per commit (L1.7)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packaging/linux/container.sh

@@ -11,7 +11,10 @@ image=ely-office-linux-build
 docker build -q -t "$image" "$root/packaging/linux" >/dev/null
 # Own target and Cargo home: host builds need newer glibc.
 mkdir -p "$root/target/ubuntu" "$root/target/ubuntu-cargo" "$root/target/ubuntu-home"
-docker run --rm --user "$(id -u):$(id -g)" -v "$root:$root" -w "$root" \
+# Engines shared from another clone resolve inside too.
+share=()
+[ -z "${ELY_SHARE:-}" ] || share=(-v "$ELY_SHARE:$ELY_SHARE")
+docker run --rm --user "$(id -u):$(id -g)" -v "$root:$root" ${share[@]+"${share[@]}"} -w "$root" \
   -e HOME="$root/target/ubuntu-home" -e CARGO_HOME="$root/target/ubuntu-cargo" \
   -e CARGO_TARGET_DIR="$root/target/ubuntu" -e ELY_RELEASE_TOKEN \
   "$image" "$@"