Lazy proxy generation via PHP 8.4 native lazy objects

[philipobenito]

Summary

Add lazy proxy support using PHP 8.4's native ReflectionClass::newLazyGhost() and ReflectionClass::newLazyProxy() APIs, allowing services to defer instantiation until first method call.

Context

Lazy proxies are useful when a service is injected as a constructor argument but may never actually be called, avoiding expensive construction costs. The committee evaluated this for 6.0 but deferred because:

• Without native lazy object support, implementing proxies requires either a code-generation library (adding a dependency) or substantial bespoke proxy class generation
• PHP 8.4 introduces ReflectionClass::newLazyGhost() and newLazyProxy() which make this trivial (approximately five lines of code)
• The current callable-as-concrete pattern already defers instantiation until get() is called, covering the majority of use cases

Implementation notes

• Requires PHP 8.4 as minimum (or feature-gated with version check)
• Could be a Definition::setLazy(bool) flag or a #[Lazy] attribute
• The compiled container would need to emit lazy ghost wrappers in factory methods
• Semantic question: when does ServiceResolvedEvent fire? When the proxy is created or when the real service is instantiated?

Target

6.2+ (when PHP 8.4 can be the minimum version)