Re-tagged to include the Rust release-build fix: pgvector pinned to =0.4.1
and --locked release builds. Original v0.5.0 tag (1a010d7) failed the
cargo test/package job because pgvector 0.4.2 pulled in sqlx 0.9 alongside
the pinned 0.8.6. Not published to PyPI or crates.io, so the version is reused.