Add data validation and improve database connection

[kaylals]

Summary

In this PR, we made several changes to enhance the functionality, scalability, and maintainability of our project:

• Pydantic Models: Implemented ClientData and PredictionInput models to validate incoming API requests and ensure data consistency. These models enforce strict typing and schema validation, reducing errors caused by invalid inputs.
• Root Endpoint: Added a root endpoint (/) to provide a basic health check for the API.
• Debugging Statements: Incorporated debugging statements (e.g., print(data.model_dump())) to simplify troubleshooting during development.

Database Management Improvements

• Centralized Database Connection: Introduced a centralized get_db function to handle MySQL connections. This approach ensures proper resource handling, including automatic connection closure.
• Error Handling: Added robust error handling for issues like invalid credentials or missing databases.
• UUID Auto-Generation: Enhanced the client creation logic by integrating UUID-based auto-generation of client IDs. This simplifies the client-side request process while maintaining unique identification for each client record.

Project Structure and Accessibility

• Modularized Codebase: Refined the project structure by separating routing, schema definitions, and database management into independent components. This improves readability and maintainability.
• CORS Middleware: Added CORS middleware to enable cross-origin requests, making the API accessible to frontend applications or external systems.

Impact

These changes collectively improve the robustness and usability of the application while laying a solid foundation for future development.