SKILL: Architecture & DDD Master Guide

This document defines the Domain-Driven Design (DDD) architecture and strict layer boundaries for the project.

🏛️ 1. Layered Architecture (The Law)

Dependencies must flow inward: Presentation → Application → Domain ← Infrastructure.

🔴 Domain Layer (src/app/domain/)

• Purity: Zero framework dependencies (No Angular, No Firebase, No RxJS).
• Entities: Minimal, intention-free models.
• Value Objects: Immutable, validated at creation.
• Repositories: Interfaces ONLY (ports).
• Aggregates: Transactional boundaries.
• Domain Events: Immutable "facts" that have occurred.