Add optimized Sieve of Eratosthenes algorithm

[Naman-Vasudev]

Describe your change:

• Add an algorithm

This PR adds an optimized implementation of the Sieve of Eratosthenes.
The optimization skips even numbers after 2 and uses a half-sized boolean array,
reducing both memory and time by approximately 50% compared to the standard sieve.

Checklist:

• I have read CONTRIBUTING.md.
• This pull request is all my own work.
• This PR only changes one algorithm file.
• All function parameters and return values are annotated with type hints.
• All functions have doctests that pass automated testing.
• All new algorithms include at least one URL that points to Wikipedia or another similar explanation.

[algorithms-keeper]

Click here to look at the relevant links ⬇️

🔗 Relevant Links

Repository:

• Contributing guidelines
• Project Euler solution guidelines

Python:

• Formatted string literals (f-strings)
• Type hints
• doctest
• unittest
• pytest

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[algorithms-keeper]

Please provide descriptive name for the parameter: n