refactor: upgrade ESLint 9→10 and simplify React lint toolchain

- Upgrade eslint and @eslint/js to v10
- Replace eslint-plugin-react-x + eslint-plugin-react-dom + eslint-plugin-react-hooks
  with unified @eslint-react/eslint-plugin
- Raise dev Node.js requirement to ^22.13.0 || >=24 (runtime packages unaffected)
- Add .npmrc with engine-strict=true
- Move all @eslint-react rule overrides to eslint.config.js,
  eliminating plugin-specific inline eslint-disable comments
- Fix real issues caught by new rules: useless assignments,
  leaked setTimeout, ref naming, useState setter naming

packages/extension/src/entrypoints/sidepanel/App.tsx

@@ -178,7 +178,6 @@ export default function App() {
 					{showEmptyState && <EmptyState />}
 
 					{history.map((event, index) => (
-						// eslint-disable-next-line react-x/no-array-index-key
 						<EventCard key={index} event={event} />
 					))}