Syncable Entity: Cache & Transform (Step 2/6)

Purpose: Create cache layer and transformation utilities to convert between different entity representations.

When to use: After completing Step 1 (Types & Constants). Required before building validators and action handlers.

Quick Start

This step creates:

1. Cache service for flat entity maps
2. Entity-to-flat conversion utility
3. Input transform utils (DTO → Universal Flat Entity)

Key principle: Input transform utils must output universal flat entities (with universalIdentifier and foreign keys mapped to universal identifiers).