Add type hints to `app.py` for better clarity

[panagiotisbellias]

Description:
Add Python type hints to functions and methods in app.py to improve
readability and developer experience.

Steps:

• Open app.py
• Add appropriate type hints for function parameters and return values
• Ensure code runs without type errors (e.g., using mypy)

Acceptance Criteria:

• All functions in app.py have clear type hints
• Code passes static type checks

[akarlaraytu]

Thanks for opening this, @panagiotisbellias! Adding type hints is a fantastic idea for improving the robustness and maintainability of app.py. I agree this is an important step.

[akarlaraytu]

For this issue, I will merge another major update for all of the components and code parts. So for a few days we can stop working on code specific issue's waiting for our major update 🚀