chore: bump version to 0.7.9

[rlippmann]

What changed

• bump the package version from 0.7.8 to 0.7.9 in pyproject.toml
• update the editable package version recorded in uv.lock to match

Why

• the version bump was missed from the earlier feature PRs and should land as its own small release-prep change
• keeping pyproject.toml and uv.lock aligned avoids packaging confusion for the release

Checklist

• pre-commit run (uv run pre-commit run --all-files)
• tests pass (uv run pytest)