Finish uv packaging migration

[j6k4m8]

This finishes the move to uv and gets the packaging metadata back to one source of truth.

• makes pyproject.toml and uv.lock authoritative
• moves Neo4j and NeuPrint support into optional extras
• derives build metadata from the package version
• switches CI to setup-uv, locked environments, and uv run
• builds and smoke-checks the wheel in CI
• stops shipping the test suite in distributions
• removes the old setuptools, requirements, and manifest files