eslint@9, prettier

[scottanderson]

• Migrate to eslint@9, including migration of various config files to modern ESM *.config.mjs format.
• Enable lint-staged.
• Report eslint errors and warnings as github annotations using eslint-gha-formatter. Annotations will appear in the files view after the github action runs.
• Add common stylistic and typescript-eslint rules.
• Reduce rules with violations to warn.