Design resource creation, cleanup, and scope using RAII, lazy initialization, and pooling patterns.

• Covers five lifecycle patterns: RAII with Drop trait, lazy initialization via OnceLock/LazyLock, connection pooling with r2d2/deadpool, guard-based scoped access, and transaction scope boundaries
• Includes decision framework for resource cost, scope determination, and error handling during cleanup
• Provides pattern templates for RAII guards and lazy singletons, plus common errors and anti-patterns to avoid
• Traces connections to ownership models (Layer 1) and domain constraints (Layer 3) for integrated design