[Advanced Rust] 1.9. Ownership (Quick Recap) - Core Ideas of Ownership, How to Implement Copy Trait, Value Drop, and Drop Order

Rust enforces a single owner per value, distinguishing moves from copies to preserve memory safety.

The `Copy` trait applies only to types where bitwise duplication is safe, such as `i32`, not heap-owning types like `Box` or `Vec`.

Values are automatically dropped when they go out of scope, and Rust uses a defined drop order to prevent double frees and invalid references.