High-level Elastic IP builder following AWS best practices. **Default Settings:** - Domain = VPC (required for VPC instances) - No instance association by default (explicit attachment) **Rationale:** These defaults follow AWS Well-Architected Framework: - VPC is the standard domain for modern AWS architectures - Explicit association prevents accidental attachments - Static IPs are expensive, use only when necessary **Use Cases:** - NAT Gateways (automatic EIP allocation) - Static IPs for public-facing services - Whitelisting with third-party services **Escape Hatch:** Access the underlying CDK CfnEIP via the `ElasticIP` property for advanced scenarios not covered by this builder.