Documentation Request: Add a simple overview explaining how OnchainKit pieces fit together

### Is your documentation request related to a problem? Please describe.

OnchainKit includes several providers, hooks, and components, but it’s not always obvious how they are meant to work together at a high level. A short, casual overview would make it easier for new users to get oriented.

### Problem Description
Developers new to OnchainKit may feel a bit lost trying to figure out which pieces they need and how data flows between them. Without a big-picture explanation, they often have to jump between docs and examples to connect the dots.

### Proposed Solution
Add a lightweight “How OnchainKit Works” section that walks through the main building blocks and their relationships in plain language. The explanation should stay high-level and friendly, without going deep into implementation details.