AbstractMemberFlagCheck

Shared orchestration for checks that compare a per-member attribute (e.g. a method's isStatic flag or a property's visibility) between reflection and stubs.

The comparison is reflection-driven: it iterates the reflection members and compares each one that also exists in the version-filtered stub member map. Members present only in reflection (or only in stubs) are ignored here — reporting those is the responsibility of the corresponding *ExistCheck.

Concrete member kinds (methods, properties) supply the member-specific behaviour via the hooks below. Constants are NOT modelled here: {\StubTests\Framework\Validator\AbstractConstantFlagCheck} iterates the stub side with per-member version filtering and different known-problem-skip semantics.

Subclasses must supply three things, one per axis plus the check's identity:

• getCheckName(): the name used for known-problem lookups
• memberKind(): which member kind to compare (see {\StubTests\Framework\Validator\Contracts\MemberKind})
• one of {\StubTests\Framework\Validator\Contracts\DescribesMethodMismatch} / {\StubTests\Framework\Validator\Contracts\DescribesPropertyMismatch}: the comparison itself

Those last two are the two axes this check varies along. They used to be expressed as one inheritance chain — a member-kind subclass per kind, with the comparison abstract below it — so adding a member kind meant adding a level. Now the kind is data and the comparison is an interface, and neither requires a new abstract class.