Add INTERNAL_README.md to GitHub directory

[atithi4dev]

Issue

Closes #(Issue number here - REQUIRED)

Description

Please describe your changes and why you're making them.

Type of Change

• 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 change)
• Documentation update
• Performance improvement
• Refactoring
• Security update

How Has This Been Tested?

Please describe how you've tested these changes:

• Unit tests
• Integration tests
• Manual testing
• Other (please describe):

Screenshots or Videos (if applicable)

If your changes involve UI or significant behavior changes, please add screenshots or videos here.

Checklist

Before submitting, please ensure:

• I have read the CONTRIBUTING.md guidelines
• My code follows the project's code style and conventions
• I have made corresponding changes to the documentation if needed
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests passed locally
• My branch name follows the pattern: feature/issue-<num>-<description> or fix/issue-<num>-<description>
• My commits are well-formatted with descriptive messages (e.g., feat(issue-45): add new feature)
• I assigned myself to the related issue using /assign @username in the issue discussion (NOT in this PR)

Related Issues or Discussions

Add any related issue numbers or discussions here (e.g., Related to #123)

Additional Context or Notes

Add any additional context or notes that might be helpful for reviewers.