update readme

[dayano74]

No description provided.

[Copilot]

Pull Request Overview

This PR significantly expands the README.md file from a basic one-line description to a comprehensive documentation for the minishell project. The update transforms a minimal repository description into a detailed project overview including technical details, contributions, and usage instructions.

• Restructures content with proper sections and markdown formatting
• Adds comprehensive project documentation including tech stack, contributions, and execution instructions
• Includes detailed usage examples demonstrating shell functionality

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