Our current Skupper documentation provides an excellent "explorer" experience, making it easy for new users to get started and see the immediate value. However, as these users become "settlers" and begin moving towards production, they run into gaps.

The Problem: Once users transition from a quick test to a production-ready environment (e.g., using their own ingress controller, custom certs, or dealing with more complex network policies), the existing documentation no longer provides enough context. 

The Solution: We need a short, succinct document that explains the fundamental architectural decisions and core concepts. This guide will serve as a reference for "settlers" who need to understand why Skupper behaves the way it does.

Proposed Content:

• Components: What are the roles of router, controller, etc 
• Service and Address Management: How Skupper exposes services and manages internal addresses.

• Routing and Data Flow: A diagram showing how data os routed between sites.

• Trust Model: A brief explanation of how Skupper sites trust each other