Create CodeBreaker.BotWithString project using string-based algorithm and add unit tests

[Copilot]

This PR implements a new string-based version of the bot project that works with the Games API using string arrays instead of binary data, as requested in the issue.

What's New

CodeBreaker.BotWithString Project:

• StringCodeBreakerAlgorithms: Core algorithms adapted from the binary version but operating entirely with string[] arrays
• StringBotGameRunner: Demonstration class showing integration with the GameAPIs client
• Complete project structure with proper configuration and documentation

CodeBreaker.BotWithString.Tests Project:

• 25 comprehensive unit tests covering all algorithms and edge cases
• Mock-based integration tests for the game runner functionality
• Full coverage of all game types (Game6x4, Game8x5, Game5x5x4)

Key Implementation Details

The string-based algorithms provide equivalent functionality to the binary version:

// Generate all possible combinations for a game
var combinations = StringCodeBreakerAlgorithms.GenerateAllPossibleCombinations(
    GameType.Game6x4, 
    new[] { "Red", "Blue", "Green", "Yellow" });

// Filter based on game results
var filtered = combinations
    .HandleBlackMatches(GameType.Game6x4, blackHits, guess)
    .HandleWhiteMatches(GameType.Game6x4, whiteHits, guess);

Benefits Over Binary Version

• Direct API compatibility: Works seamlessly with IGamesClient string-based methods
• Improved readability: String operations are more intuitive than bit manipulation
• Easier debugging: Color names are human-readable throughout the algorithm
• Simplified logic: No bit masks, shifts, or binary encoding required

Testing Coverage

All algorithms are thoroughly tested with scenarios including:

• Exact position matches (black hits)
• Correct color, wrong position matches (white hits)
• Partial matches for Game5x5x4 (blue hits)
• No matches filtering
• Edge cases and error conditions
• Game runner integration with various scenarios

The implementation maintains the same algorithmic approach as the original binary version while providing a more accessible string-based interface for future benchmark comparisons.

Fixes #318.

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