feat: add __main__.py for CLI usage with python -m whisper_timestamped

[TOduah]

Summary

This adds a __main__.py file so the whisper_timestamped package can be run directly from the terminal using:

python -m whisper_timestamped --input your_audio_file.wav

This makes it easier to run the tool without needing to write a separate script or manually call internal functions.

Example

python -m whisper_timestamped --input audio.wav --model base --language en

Notes

This change maintains full backward compatibility and does not interfere with existing imports or usage as a Python module.