Add support for tracking Container<Pointer>

```cpp
#include

struct [[gsl::Owner]] T {};

struct [[gsl::Pointer]] S {
S(const T&);
};

std::optional f3() {
T t;
return S(t); // No error
}
```

Start by reproducing the supplied C++ example and tracing the existing tracking of gsl::Owner and gsl::Pointer values. Identify where std::optional is handled and determine how container-held pointers are represented. Done means the example produces the expected lifetime diagnostic without breaking existing tracking behavior.

Written by the indexing model from the issue text.