packaging(python): sync python crate version and lockfile with the Rust crate

[joshrotenberg]

Summary

The Python package metadata and lockfile are out of sync with the main Rust crate.

Evidence

• root crate version is 0.9.5 in Cargo.toml
• Python crate version is still 0.9.3 in python/Cargo.toml
• running cargo test --manifest-path python/Cargo.toml updates python/Cargo.lock substantially, which indicates the checked-in lockfile is stale

Why this matters

• the Python extension's reported package version can drift from the main crate/release notes
• stale lockfiles create noisy diffs and reduce confidence in release reproducibility
• release/debugging work for issue Python package publish failing #48 gets harder when versioning state is ambiguous

Relevant files

• Cargo.toml:3
• python/Cargo.toml:3
• python/Cargo.lock
• python/src/lib.rs uses env!("CARGO_PKG_VERSION") for __version__

Suggested direction

• decide which manifest is the source of truth for Python package versioning
• keep the Python crate version aligned with the intended released package version
• refresh and commit python/Cargo.lock
• document when the Python lockfile should be regenerated and whether CI should enforce it

Acceptance criteria

• Python package versioning is intentionally aligned with the release process
• python/Cargo.lock is current and stable in CI
• building the Python extension reports the expected version
• release docs/workflows reflect the chosen source of truth