Add --find-links to backend builds to ensure they use the locally built leann-core with fixed MLX dependencies instead of downloading from PyPI. Also bump leann-core version to 0.2.8 to ensure clean dependency resolution.
Add --find-links to backend builds to ensure they use the locally built leann-core with fixed MLX dependencies instead of downloading from PyPI. Also bump leann-core version to 0.2.8 to ensure clean dependency resolution.