Bug 306043 – Adopt LIFETIME_BOUND for WTF::Expected

• Status: RESOLVED
• Resolution: FIXED
• Component: Web Template Framework

[David Kilzer (:ddkilzer)]

Add LIFETIME_BOUND attribute to operator->, operator*, value(), and error() methods in Expected<T,E> template class to prevent unsafe uses that could lead to dangling references.

The following methods will be updated to include LIFETIME_BOUND:
```cpp
// Pointer access methods
constexpr const value_type* operator->() const LIFETIME_BOUND;
value_type* operator->() LIFETIME_BOUND;

// Reference access methods  
constexpr const value_type& operator*() const & LIFETIME_BOUND;
value_type& operator*() & LIFETIME_BOUND;
constexpr const value_type&& operator*() const && LIFETIME_BOUND;
constexpr value_type&& operator*() && LIFETIME_BOUND;

// Value access methods
constexpr const value_type& value() const & LIFETIME_BOUND;
constexpr value_type& value() & LIFETIME_BOUND;
constexpr const value_type&& value() const && LIFETIME_BOUND;
constexpr value_type&& value() && LIFETIME_BOUND;

// Error access methods
constexpr const error_type& error() const & LIFETIME_BOUND;
error_type& error() & LIFETIME_BOUND;
constexpr error_type&& error() && LIFETIME_BOUND;
constexpr const error_type&& error() const && LIFETIME_BOUND;
```

[Radar WebKit Bug Importer]

<rdar://problem/168699050>

[David Kilzer (:ddkilzer)]

Pull request: https://github.com/WebKit/WebKit/pull/57067

[EWS]

Committed 306108@main (fb63b305a9c2): <https://commits.webkit.org/306108@main>

Reviewed commits have been landed. Closing PR #57067 and removing active labels.