How do you effectively distinguish between a Senior DevOps Engineer and a Platform Engineer when their technical toolkits—Kubernetes, Terraform, and CI/CD pipelines—are virtually identical? Furthermore, while a Senior DevOps role often focuses on high-level delivery and incident response for specific products, Platform Engineering treats infrastructure as a product for internal developers. Why is the shift from "solving problems for teams" to "building self-service systems that solve problems at scale" the defining characteristic of this transition?