Migrate from ESLint to Oxlint

Replace the per-package ESLint flat configs and shared base configs with a
single root .oxlintrc.json generated via @oxlint/migrate, including type-aware
rules (oxlint-tsgolint).

- Add .oxlintrc.json with unified TS/React/Jest rules and typeAware enabled
- Delete 34 per-package eslint.config.*, 6 root eslint base configs,
  .eslintignore, and the dead legacy extension/test/.eslintrc
- Swap all `eslint .` lint scripts to `oxlint` (oxlint resolves the root config
  from each package dir)
- Remove all ESLint dependencies; add oxlint and oxlint-tsgolint
- Preserve prior behavior: ignore emotion `css` in react/no-unknown-property,
  and oxlint-disable the 3 prefer-regexp-exec sites on non-literal regexes
- .gitignore: .eslintcache -> .oxlintcache

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: Methuselah96

.eslintignore

@@ -7,7 +7,7 @@ umd
 build
 coverage
 .idea
-.eslintcache
+.oxlintcache
 !packages/redux-devtools-slider-monitor/examples/todomvc/dist/index.html
 .nx
 *.tsbuildinfo