docs: rewrite README with quick start, features, and usage guide; migrate setup.py to pyproject.toml with improved metadata

Author: erinshek

README.md

@@ -96,12 +96,4 @@ lat2cyr input.txt output.txt   # writes output.txt
 - **Not a translator** — it converts scripts (Latin ↔ Cyrillic), not languages
 - **Not a spell-checker** — it does not validate or correct Karakalpak text
 - **Not for other Turkic languages** — Kazakh, Uzbek, Turkish, etc. have different alphabets and rules
-- **Not an OCR tool** — it works with digital text, not images
-
-## Contributing
-
-See [CONTRIBUTING.md](CONTRIBUTING.md).
-
-## License
-
-[MIT](LICENSE)
+- **Not an OCR tool** — it works with digital text, not images