docs: add lesson design best practices to CLAUDE.md

Document learnings for creating effective lessons:
- Clear task instructions with selector and property
- Use codePrefix for context
- Simple, human-friendly values
- Named CSS colors for engagement
- Focused validations
- Semantic HTML in examples

README.md

@@ -44,7 +44,7 @@ Code Crispies is a web-based learning platform designed to help users master CSS
 
 1. Clone the repository:
    ```bash
-   git clone https://github.com/nextlevelshit/code-crispies.git
+   git clone https://git.librete.ch/libretech/code-crispies.git
    cd code-crispies
    ```
 
@@ -244,4 +244,4 @@ When adding new lessons:
 
 ## 📄 License
 
-Copyright (c) 2025 Michael Czechowski. Licensed under the [./LICENSE](WTFPL).
+Copyright (c) 2025 Michael Czechowski. Licensed under the [./LICENSE](WTFPL).