generic types, traits and lifetimes

- get claude to create rustlings style exercises based on chapter 10 of the book
- update CLAUDE.md to prevent it from producing incorrect exercises
- complete exercises/01-generic-cache-system

exercises/03-basic-traits/README.md

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+# Configuration System Traits
+
+Build a configuration system where different components (database, cache, logger) can be configured uniformly. You'll define traits that allow different types to be configured, validated, and reset in a standard way.
+
+## What you'll practice
+
+- Defining traits that establish contracts between types
+- Implementing the same trait for different struct types
+- Using traits as function parameters with `impl Trait` syntax
+- Creating functions that work with any type implementing specific traits
+
+## Further information
+
+- [Traits: Defining Shared Behavior](https://doc.rust-lang.org/book/ch10-02-traits.html)
+- [Traits as Parameters](https://doc.rust-lang.org/book/ch10-02-traits.html#traits-as-parameters)