feat:added minimum palindromic insertion

[Arpita23r]

• Implemented Minimum Palindrome Insertion algorithm in R to determine the fewest characters needed to make a string a palindrome.
• Uses dynamic programming for efficient computation (O(n²) time and space).
• Reconstructs and prints one possible resulting palindrome.
• Handles both odd and even length strings.
• Supports case-insensitive input for flexible string matching.
• Includes interactive user input to test different strings easily.
• Stored file under string_manipulation/min.palindrome.insertion.R following project structure conventions.

[Copilot]

Pull Request Overview

This PR implements a minimum palindromic insertion algorithm in R that calculates the fewest characters needed to make a string a palindrome using dynamic programming. The algorithm also reconstructs and displays one possible resulting palindrome.

• Adds dynamic programming solution with O(n²) time and space complexity
• Implements palindrome reconstruction to show the actual result
• Includes interactive user input with case-insensitive processing

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