Refactor TypeTracker logic for live word updates and session reset after timer completion

[ignabelitzky]

This pull request refactors the TypeTracker behavior to improve usability and accuracy during typing sessions. The main changes include:

• Instant word updates:
  The displayed word now updates dynimically as the user types (QLineEdit::textChanged signal) instead of relying on the timer tick. This provides real-time feedback and a smoother typing experience.

• Proper session reset:
  After the timer reaches one minutr or all words are completed, a QMessageBox shows the user's WPM, total characters typed, and accuracy. Once the user closes the dialog, the session is fully reset -- clearing counters, text fields, and disabling input until "Start" is pressed again.

• Cleaner initialization:
  Simplified the onStartButtonClicked() method to always reset state and show the first word immediately at the start of a session.

These changes make the typing tracker more responsive, robust, and user-friendly while maintaining the code timing and accuracy features.

[ignabelitzky]

Hi @danilosramos could you please checkout this Pull Request?