(PULLED) Lazy-load OpenMM and improve type annotations

This release has been pulled because of a corner case not easily detected pre-production

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What's Changed

• Typing improvements by @mattwthompson in #84
• Drop Python 3.9 by @mattwthompson in #85
• [pre-commit.ci] pre-commit autoupdate by @pre-commit-ci in #86
• [pre-commit.ci] pre-commit autoupdate by @pre-commit-ci in #90
• Add "Kelvin" unit by @mattwthompson in #91
• Migrate formatting to use ruff by @mattwthompson in #95
• Bump mamba-org/setup-micromamba from 1 to 2 by @dependabot in #93
• Lazy load objects at top level by @mattwthompson in #97
• [pre-commit.ci] pre-commit autoupdate by @pre-commit-ci in #96

Full Changelog: 0.2.2...0.2.3