Upgrade ESLint to v9 with flat config (#9680)
* Upgrade ESLint to v9 with flat config
- Upgrade eslint from v8 to v9.18.0
- Migrate from .eslintrc.js to eslint.config.mjs (flat config)
- Upgrade typescript-eslint to v8.20.0 (unified package)
- Replace eslint-plugin-import with eslint-plugin-import-x for flat config support
- Add globals package for environment globals
- Update eslint-plugin-bsky-internal with proper meta objects for ESLint v9
- Fix deprecated context.getScope() API usage
- Update bskyembed to use flat config
- Remove deprecated --ext flag from lint scripts
- Configure rules to maintain previous behavior while using new ESLint version
* Fix varsIgnorePattern to require character after underscore
Restore the original pattern `^_.+` instead of `^_` so that lingui's
`const { _ } = useLingui()` will still be flagged when unused.
* Update ESLint rule tests for flat config format
- Update RuleTester to use flat config languageOptions instead of
eslintrc parser format
- Remove duplicate test case that ESLint v9 now detects
- Add Jest globals for test files
* update eslint package versions
* lint android a11y
* enable typechecked rules, switch them to warn
* fix yarn lock ci
* Fix CI failure
* Remove unused globals?
* Organize a bit, add quiet to main lint command
* Allow ternary
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Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Eric Bailey <git@esb.lol>