Add quicksort algorithm

Description

Add quicksort algorithm implementation to the sorting library.

Requirements

1. Implement classic quicksort algorithm using list comprehensions
2. Implement in-place quicksort algorithm using Hoare partition scheme
3. Add both implementations to sort.py
4. Update test_sort.py to include tests for both quicksort variants
5. Ensure proper error handling and edge cases

Acceptance Criteria

• Both quicksort implementations are added to sort.py
• Tests pass for both implementations
• Time and space complexity documented
• Edge cases handled (empty list, single element, already sorted, reverse sorted)

Labels

enhancement, algorithm

Milestone

v1.1.0