feat: Add more classic sorting algorithms to the visualizer

To make this tool more comprehensive and educational, we need to expand our library of sorting algorithms. This issue is a call for help to implement several well-known algorithms that work perfectly with a bar chart visualization.

How to Contribute: Choose ONE algorithm from the list below that has not yet been claimed by another user.

Comment on this issue to claim it (e.g., "I'll take on Merge Sort"). This prevents duplicate work.

Implement the sorting logic as a Python generator function. It must yield the full array state (and ideally the indices being compared/swapped) after every single step.

Add the new algorithm's name to the selection dropdown in the Streamlit UI.

Create a pull request with your changes.

Algorithms to Add: [ ] Merge Sort

[ ] Heap Sort

[ ] Selection Sort

[ ] Insertion Sort

[ ] Cocktail Shaker Sort (a fun bi-directional bubble sort)

[ ] Shell Sort