Add AV0110: Prefer composition over class inheritance

_rules/0110.md

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+---
+rule_id: 0110
+rule_category: general
+title: Prefer composition over class inheritance
+severity: 2
+---
+Inheritance creates a tight coupling between a base class and its derived classes. Any change to the base class can unexpectedly break derived classes, and the inheritance hierarchy can become difficult to understand as it grows. Composition — building behavior by combining small, focused objects or interfaces — avoids these problems.
+
+Prefer composition when:
+- The relationship is "has-a" rather than "is-a".
+- You want to reuse behavior without exposing or depending on the internals of another class.
+- You need to vary behavior at runtime (e.g. through the [Strategy pattern](https://en.wikipedia.org/wiki/Strategy_pattern)).
+
+**Exception:** Inheritance is appropriate when a true "is-a" relationship exists and when derived classes genuinely extend (rather than replace) the behavior of their base class. Always follow the [Liskov Substitution Principle](https://en.wikipedia.org/wiki/Liskov_substitution_principle) when using inheritance.