Fix no-extraneous-import for type-only @types dependencies

[sjh9714]

Summary

Fixes no-extraneous-import for type-only imports backed by @types/* dependencies.

What changed

• Added regression coverage for import type and export type from a package with only its @types/* package declared.
• Allowed type-only import/export targets when the matching DefinitelyTyped package is declared.
• Preserved extraneous reports for runtime imports and exports.

Why

Issue #486 reports that TypeScript type-only imports from packages such as picomatch are reported as extraneous even when @types/picomatch is installed directly.

Testing

• npm run test:mocha -- tests/lib/rules/no-extraneous-import.js
• npm run lint
• npm run test:types
• npm test
• git diff --check

Fixes #486

[aladdin-add]

LGTM, thanks! 💯