feat:allow multiple markdown files in projects

[dharapandya85]

Description

Type of Change

This PR introduces handling of multiple markdown files in a project. Now, users can add, switch between, and also edit multiple markdown files, with drag and drop, and import feature.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Documentation update
• Code refactoring
• Performance improvement
• UI/UX improvement

Related Issue

Closes #11

Changes Made

• Implemented drag-and-drop import for .md files
• Feature of open and edit markdown files simultaneously

Screenshots (if applicable)

Before	After

Checklist

• My code follows the project's code style
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have tested my changes locally
• Any dependent changes have been merged and published

Additional Notes