pip's backtracking resolver hits 'resolution-too-deep' on complex
dependency graphs (robomme → mani-skill, libero_plus → robosuite/bddl).
uv resolves the same graphs in seconds without backtracking issues.
Also removes the now-redundant PATH= prefix since uv and python are
already on PATH via the base image ENV.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>