docs(README.md): add process diagram image to README

feat(assets): add OpenAI-TreeThoughtSolver.png image to assets
The README file now includes a process diagram image to provide a visual representation of the OpenAI Tree-Based Problem Solver's workflow. This addition enhances the project's documentation by making it easier for users to understand how the tool works. The image file has been added to the assets directory.

Author: Sébastien Fichot

README.md

@@ -2,6 +2,8 @@
 
 The OpenAI Tree-Based Problem Solver is an open-source project that leverages the power of OpenAI's language models to solve problems presented in a structured format. The program uses a chained prompt technique and tree-based thought process to iteratively refine solutions to complex problems. The idea was inspired by a YouTube video and has been developed into a functional tool.
 
+![Process](./assets/OpenAI-TreeThoughtSolver.png)
+
 ## System Requirements
 Before getting started, ensure you have the following: