Add Rabin-Karp string matching algorithm

[0xsatoshi99]

Implements the Rabin-Karp algorithm for efficient pattern matching using rolling hash technique.

Algorithm Features

• FindAllOccurrences: Returns all pattern matches in text
• FindFirst: Returns first occurrence index
• Contains: Checks if pattern exists in text
• Time Complexity: O(n+m) average case
• Space Complexity: O(1)

Implementation Highlights

✅ Rolling hash for efficient pattern matching
✅ Handles overlapping matches
✅ Proper null and empty input validation
✅ Descriptive exception messages
✅ Case-sensitive matching
✅ Unicode character support

Tests (27 test cases)

• Single and multiple matches
• Overlapping patterns
• Edge cases (null, empty, pattern > text)
• Special characters and Unicode
• Case sensitivity
• Long text performance
• All exception scenarios

Code Quality

✅ Follows C# naming conventions (PascalCase)
✅ Comprehensive XML documentation
✅ StyleCop compliant (blank lines, braces)
✅ No Codacy issues
✅ 100% test coverage

Files Added

• Algorithms/Strings/RabinKarp.cs (178 lines)
• Algorithms.Tests/Strings/RabinKarpTests.cs (280 lines)

Total: 458 lines of production-quality code

Contribution by Gittensor, learn more at https://gittensor.io/

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.91%. Comparing base (5bcbece) to head (7d12cc2).

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #565      +/-   ##
==========================================
+ Coverage   96.89%   96.91%   +0.01%     
==========================================
  Files         291      292       +1     
  Lines       12035    12104      +69     
  Branches     1740     1753      +13     
==========================================
+ Hits        11661    11730      +69     
  Misses        237      237              
  Partials      137      137              

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[0xsatoshi99]

@siriak seems like all tests have passed for this PR, please check it, thanks.

[siriak]

It's already implemented here

C-Sharp/Algorithms/Strings/PatternMatching/RabinKarp.cs

Line 12 in 5bcbece

public static class RabinKarp