I plan to add a CODEBASE_EXPLANATION.md file to document the reposito…

This pull request adds a new `CODEBASE_EXPLANATION.md` file, which provides a detailed overview of the codebase's architecture, directory structure, and the purpose of key files and components. The document is intended to serve as a comprehensive guide for developers to understand the project's structure and functionality. ### Key Additions: #### Codebase Overview: * Introduces an in-depth explanation of the project's architecture, featuring core technologies like Next.js, tRPC, Prisma, NextAuth.js, Tailwind CSS, and TypeScript. #### Directory and File Descriptions: * Details the purpose of root directory files (e.g., `.env.example`, `package.json`, `next.config.mjs`) and their roles in configuration, dependency management, and build processes. * Explains the structure and functionality of key directories, including: - [`src/components/`](diffhunk://#diff-22c46640fba11a9ac962d39d8ccf2d6b892a70e94f9542637ccf528add351ccdR1-R145): Reusable UI components like `ChatWindow`, `Button`, and animations from `motions/`. - [`src/env/`](diffhunk://#diff-22c46640fba11a9ac962d39d8ccf2d6b892a70e94f9542637ccf528add351ccdR1-R145): Environment variable management and validation using Zod schemas. - [`src/server/`](diffhunk://#diff-22c46640fba11a9ac962d39d8ccf2d6b892a70e94f9542637ccf528add351ccdR1-R145): Backend logic for tRPC routers, authentication, and database initialization. - `src/utils/`: Utility functions for API interactions and AI logic using LangChain and OpenAI's