feat: Adiciona solução TDD para problema 8 (atoi) na liguagem python

[MarcusVcd]

Pull Request Template

Description

This PR adds a TDD-based solution for the LeetCode problem #8, "String to Integer (atoi)", implemented in Python.

The solution iteratively processes the string, handling leading whitespace, optional signs, and numerical digits, while also managing 32-bit integer overflow and underflow conditions as required by the problem description.

Problem Link: https://leetcode.com/problems/string-to-integer-atoi/

Put check marks:

• Have you made changes in README file ?
• Added problem & solution under correct topic.
• Specified Space & Time complexity.
  • Time Complexity: O(n), where n is the length of the string, as we do a single pass.
  • Space Complexity: O(1), as we only use a few variables to store state.
• Specified difficulty level, tag & Note(if any).
  • Difficulty: Medium
  • Tags: String, Math

How Has This Been Tested?

The solution was developed using Test-Driven Development (TDD). A suite of unit tests was created using pytest to verify each piece of functionality incrementally. The tests cover:

• Basic positive integer conversion.
• Handling of leading whitespace and signs (+/-).
• Correctly stopping at non-digit characters.
• Clamping to INT_MAX on overflow.
• Clamping to INT_MIN on underflow.

Make sure all below guidelines are followed else PR will get Reject:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code so that it is easy to understand
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• Any dependent changes have been merged and published in downstream modules

[welcome]

I can tell this is your first pull request! Thank you I'm so honored. 🎉🎉🎉 I'll take a look at it ASAP!