Switch from pip to uv for dependency management
Replace pip with uv across the Makefile for faster, reproducible installs
with a committed lock file. This makes git worktrees safe and efficient
since each worktree runs `uv sync` against the shared uv.lock while uv's
global cache avoids redundant downloads.
Key changes:
- Makefile: all pip calls replaced with uv/uv pip equivalents
- uv.lock: generated and committed for reproducible builds
- pyproject.toml: add [tool.uv] constraint for numba>=0.60
- Rename `make update-deps` to `make update`
- Move genai-prices upgrade from install to `make update`
- Fix onnxruntime nightly install ordering (after uv sync)
- Update all docs to reference uv/make install instead of pip
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>