feat: Add Z Algorithm string search in R

[Arpita23r]

• Implemented Z Algorithm for pattern searching in R.
• Efficient linear-time string matching using prefix computation.
• Handles case-insensitive input.
• Returns all positions of pattern occurrences in text.
• Time Complexity: O(n + m)
• Space Complexity: O(n)
• Added interactive user input for testing.

[Arpita23r]

Hi maintainers 👋, this is my first contribution. The checks are waiting for approval — please approve workflow runs. Thank you!

[Copilot]

Pull Request Overview

This PR implements the Z Algorithm for efficient string pattern searching in R. The algorithm performs linear-time string matching using prefix computation and provides case-insensitive pattern searching functionality.

Key changes:

• Added Z Algorithm implementation with O(n + m) time complexity
• Included interactive user input for testing the algorithm
• Implemented case-insensitive string matching

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[siriak]

Looks good, thanks!