chore(bindings): move rust crate to crates/lance-graph-python

[beinan]

Summary

• move PyO3 Rust crate from python/ to crates/lance-graph-python
• wire new manifest into workspace, maturin config, Makefile, docs, examples, and release workflow
• rebuild bindings and run Python tests to validate relocation

Testing

• cargo check --workspace
• uv run --project . maturin develop
• uv run --project . pytest python/tests -vv

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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