strategy-pattern-go

# Strategy Pattern (Go Backend)

**Why:** Strategy lets you define a family of algorithms, put each in a separate type, and make them interchangeable so the context stays stable while behavior is swapped at runtime ([Refactoring.Guru](https://refactoring.guru/design-patterns/strategy)).

**Hard constraints:** Context must depend only on a strategy interface, not concrete implementations. Use composition (context holds an interface value); avoid embedding or inheritance for variant behavior. Keep each strategy in its own type/package when it has real logic.