feat: add multi-layer caching strategy from kogotochki

[talkstream]

Summary

This PR introduces a sophisticated multi-layer caching system inspired by kogotochki's implementation for high-performance data access. The system provides automatic cache population between layers and intelligent TTL management.

Key Features

• Generic MultiLayerCache service with configurable cache layers
• Automatic layer population - when data is found in a slower layer, it's automatically copied to faster layers
• Three cache adapters:
  • EdgeCacheAdapter - Uses Cloudflare's Cache API for ultra-fast edge caching
  • KVCacheAdapter - Works with any IKeyValueStore (KV, Redis, etc.)
  • MemoryCacheAdapter - In-memory caching for single instances
• Tag-based invalidation - Invalidate groups of related cache entries
• Pattern-based invalidation - Invalidate entries matching regex patterns
• Cache statistics - Track hit rates and layer efficiency
• Cache warmup - Pre-populate cache with commonly accessed data

Architecture

┌─────────────┐     ┌─────────────┐     ┌─────────────┐
│   L1: Edge  │ --> │  L2: KV     │ --> │ L3: Database│
│  (fastest)  │     │   (fast)    │     │  (slowest)  │
└─────────────┘     └─────────────┘     └─────────────┘
       ↑                    ↑                    │
       └────────────────────┴────────────────────┘
              Auto-population on cache hit

Usage Example

const cache = new MultiLayerCache({
  layers: [
    new EdgeCacheAdapter({ baseUrl: 'https://cache.example.com' }),
    new KVCacheAdapter(kvNamespace, { prefix: 'app:' }),
    new MemoryCacheAdapter(),
  ],
  defaultTTL: 300,
  populateUpperLayers: true,
  logger: logger,
});

// Basic usage
const value = await cache.get('user:123');

// Cache-aside pattern
const user = await cache.getOrSet('user:123', async () => {
  return await database.getUser(123);
}, { ttl: 3600, tags: ['users'] });

Origin

This pattern was extracted from kogotochki's Top3CacheService which implements a 3-layer cache for auction winners with intelligent TTL calculation based on auction periods.

Testing

• Comprehensive test suite with 23 tests covering all functionality
• All tests passing
• TypeScript strict mode compliant
• Zero ESLint warnings

Documentation

Complete documentation added in docs/patterns/multi-layer-caching.md with examples and best practices.