fix: prepare 0.2.2 patch release with duroxide-pg 0.1.37 - #29

Summary

• Prepare patch release 0.2.2, with matching versions in Cargo.toml and pyproject.toml.
• Upgrade duroxide-pg from 0.1.36 to the latest published version, 0.1.37.
• Move the dependency changelog entry into 0.2.2, dated 2026-10-21, leaving an empty Unreleased section.
• Keep registry dependencies without local path overrides.

Validation

• Confirmed the latest published provider version using cargo info duroxide-pg.
• Release metadata consistency checks passed.
• maturin develop and the existing SQLite orchestration smoke check passed for 0.2.2.
• git diff --check passed.
• PostgreSQL integration tests were not run locally.
• CI tests, both macOS builds, Windows, Linux ARM64, and sdist passed for the release-preparation commit.
• Linux x86_64 wheel build remains in progress. The preceding commit's successful x86_64 job spent approximately 23 minutes fetching AlmaLinux repository metadata before compiling Rust in 2m41s.

SDK symmetry

Checked microsoft/duroxide-node: it still uses duroxide-pg 0.1.36. No sibling Node SDK checkout is available in this workspace.

Publishing and release tagging are not part of this PR preparation.