Added Topological Sort (DFS-based) Algorithm in Python

[komalsrivastava282]

This PR adds an original implementation of the Topological Sort algorithm in Python using Depth-First Search. It computes a linear ordering of vertices in a Directed Acyclic Graph (DAG).

The code is clean, well-documented, and includes multiple test cases covering standard and edge scenarios. It follows Python best practices and contribution guidelines.

✅ Features:

• DFS-based topological sorting
• Time Complexity: O(V + E)
• Space Complexity: O(V)
• Five test cases
• Inline comments and top-level docstring

[github-actions]

🎉 Welcome to Hacktoberfest 2025, @komalsrivastava282! 🎃

Thank you for your first contribution to our DSA repository! Here's what happens next:

🔍 Automatic Checks

• ✅ Code Validation: Passed
• 🧪 Compilation Tests: Passed

📋 Next Steps

🎯 Great job! Your code compiled successfully. Maintainers @Karanjot786 and @Pradeepsingh61 will review your PR soon.

🎁 What You Get

• 🏆 Hacktoberfest Credit: This PR counts toward your 6 PR goal for exclusive T-shirt + Tree!
• 🌟 Hall of Fame: You'll be featured in our contributors list
• 📚 Learning: Code review feedback from experienced developers

💡 Tips for Success

• Follow our Contributing Guidelines
• Add comments explaining your algorithm
• Include time/space complexity analysis
• Test your code before submitting

Welcome to the community! 🚀

[github-actions]

🤖 Automated PR Status

🔍 Code Validation

✅ Passed - File naming and structure look good!

🧪 Compilation Tests

✅ Passed - All code compiles successfully!

📋 Overall Status

🎉 Ready for Review - Your PR has passed all automated checks!
👥 Maintainers have been notified for review.

---

This comment was generated automatically. Checks will re-run when you push new commits.