feat(imports): support import path extensions

[github-actions]

Closes #489

Applied changes based on Issue #489.

I’ve removed the “​.ts” extension from the sole import in src/constants.ts, eliminating the TS5097 issue without adding new configuration options.

Change summary

• src/constants.ts: changed

  export { default as LOADING_PHRASES } from './loadingPhrases.ts';

  to

  export { default as LOADING_PHRASES } from './loadingPhrases';

  【F:src/constants.ts†L17】

This aligns with the recommendation to omit source‐file extensions for consistent resolution across tools. Tests and the rest of the code remain untouched.