Implement cached sequence walkers for optimized isElement function calls

[konard]

🎯 Summary

This pull request implements cached versions of sequence walkers to optimize performance by caching the results of isElement function calls, directly addressing issue #32.

📋 Issue Reference

Fixes #32

✨ Changes Made

🆕 New Classes:

• CachedSequenceWalkerBase<TLinkAddress>: Abstract base class that extends SequenceWalkerBase with caching functionality for isElement calls
• CachedLeftSequenceWalker<TLinkAddress>: Cached version of LeftSequenceWalker
• CachedRightSequenceWalker<TLinkAddress>: Cached version of RightSequenceWalker
• CachedLeveledSequenceWalker<TLinkAddress>: Cached version of LeveledSequenceWalker

🔧 Features:

• Dictionary-based caching to store isElement results per link address
• ClearCache() method to reset cache when needed
• GetCacheSize() method for cache inspection and debugging
• Same constructors as original walkers for drop-in compatibility
• All original functionality preserved with performance optimization

✅ Tests:

• CachedWalkersTests: Unit tests validating caching behavior and constructor functionality
• Tests verify that cached calls reduce isElement function invocations
• Tests ensure cache management methods work correctly

🚀 Performance Benefits:

• Reduces repeated isElement function calls for the same link addresses
• Especially beneficial for sequence traversals that revisit elements
• Maintains identical behavior to original walkers while improving performance

🧪 Test Results:

• All tests pass (58/58)
• Build succeeds without errors or warnings
• Cached walkers demonstrate reduced function call overhead in tests

💡 Usage:

// Drop-in replacement for existing walkers
var cachedLeftWalker = new CachedLeftSequenceWalker<ulong>(links, stack);
var cachedRightWalker = new CachedRightSequenceWalker<ulong>(links, stack);
var cachedLeveledWalker = new CachedLeveledSequenceWalker<ulong>(links);

// Cache management
cachedWalker.ClearCache(); // Reset cache
var size = cachedWalker.GetCacheSize(); // Monitor cache size

🤖 Generated with Claude Code