refactor structure

[Omid2831]

This pull request reorganizes and improves the documentation for the Bubble Chart Application, and introduces a new FastAPI server entry point with basic database connectivity and security checks. The main changes are the migration and enhancement of the project README, and the addition of a FastAPI app with a database test endpoint.

Documentation improvements and restructuring:

• The main project documentation was moved from README.md to server/README.md, with expanded details about features, data flow, dependencies, and collaboration options. The new README now includes information about CSV export, AI-powered predictions, PDF report generation, and a flow diagram for better clarity. [1] [2]

Backend server initialization:

• Added server/src/main.py to initialize a FastAPI application, including endpoints for root and database testing, and a security check to restrict database access to specific tables.

Database connectivity and security:

• The /test-db endpoint in main.py verifies the table name against an allowed list to prevent SQL injection, and fetches data from the database with proper connection management.

Dependency updates:

• The new README lists additional dependencies like pandas, matplotlib, numpy, reportlab, and openai, highlighting expanded functionality for data manipulation, visualization, PDF generation, and AI predictions.

Collaboration and contribution guidelines:

• The updated documentation encourages collaboration and contributions, making it easier for new developers to get started and understand the project scope.