Bundle libxml2 + ICU in the baremetal package so it runs on newer distros (fixes #4362)

[exzile]

Problem

The baremetal Linux release tarball fails to start on distros newer than the build base, because it does not bundle libxml2 — a runtime dependency of the ovms binary.

ldd /opt/ovms/bin/ovms reports libxml2.so.2 => not found. create_package.sh bundles the bazel-out artifacts plus the OpenVINO/OpenCV/TBB/OpenCL libraries, but libxml2 is pulled in from the base image (Dockerfile.ubuntu apt-get install ... libxml2), so the portable tarball never included it. On Ubuntu 22.04/24.04 the host provides libxml2.so.2, masking the gap. On a host whose libxml2/ICU soname differs it breaks — e.g. Ubuntu 26.04 ships libxml2.so.16 + ICU 78 (no libxml2.so.2, no ICU 74):

ovms: error while loading shared libraries: libxml2.so.2: cannot open shared object file: No such file or directory

The full unmet chain (via readelf -d) is ovms → libxml2.so.2 → libicuuc.so.74 → libicudata.so.74.

Reported in #4362.

Fix

Bundle libxml2 and its ICU dependency chain into /ovms_release/lib/ in create_package.sh, alongside the existing libOpenCL copy and before the patchelf --set-rpath '$ORIGIN/../lib' pass, so the copied libraries get an rpath that resolves them within the package.

if [[ "$BASE_OS" =~ "ubuntu" ]] ; then
	cp -P /usr/lib/x86_64-linux-gnu/libxml2.so.2* /ovms_release/lib/
	cp -P /usr/lib/x86_64-linux-gnu/libicuuc.so.* /ovms_release/lib/
	cp -P /usr/lib/x86_64-linux-gnu/libicudata.so.* /ovms_release/lib/
fi

Only the minimal chain is bundled — libz, liblzma, libstdc++, libm, libc have stable sonames present on every target and are intentionally left to the host.

Verification

On Ubuntu 26.04 (glibc 2.43), with the current v2026.2.1 ovms_ubuntu24 tarball the binary won't start (libxml2.so.2: cannot open shared object file). After adding these three libraries to ovms/lib/, ldd ovms is fully resolved and OVMS starts and serves an LLM on the GPU (Intel Arc Pro B60) end-to-end via /v3/chat/completions. This PR makes create_package.sh produce that self-contained tarball directly.

Notes / scope

• ubuntu x86_64 only. This is the reported and verified case. The redhat package (and aarch64) likely need the analogous copy from their own libdirs, but I could only verify ubuntu x86_64, so I left them untouched rather than ship unverified paths.
• Size: adds ~30 MB, almost entirely libicudata (the ICU data blob libxml2 requires). If that's a concern, an alternative is to link a libxml2 built --without-icu (or statically), which would avoid bundling ICU — happy to pursue that direction instead if maintainers prefer.
• Licenses: libxml2 (MIT) and ICU (Unicode license) are now shipped in the tarball; thirdparty-licenses/ may want their texts added.