Fix interface union parsing after ::class references

[daniel-cannon]

Summary

• stop treating ::class constant fetches as real class declarations when locating the model class token
• add a regression fixture and test for an attribute containing both ParentAnimal::class and an enum case
• keep the recent chunk-boundary fix intact while restoring correct interface-union generation for real Laravel models

Context

This fixes a regression introduced by the newer class declaration parser.

In consuming apps like fbg-app, models with attributes such as:

• #[MentionableDto(MemberData::class, MentionablePrefix::Member, 'name')]

could be parsed incorrectly, causing the generator to treat MentionablePrefix as the model class and emit invalid unions such as App\\Models\\MentionablePrefix.

Effect

This restores correct output for interface unions like Historiable, FileUploadable, Invoiceable, and Orderer in real app usage.