fix: avoid faulty duplicate detection (#893)

* fix: avoid faulty duplicate detection

bug caused by missing reflection type name for inline struct definitions, combined with an empty OperationID

* fix: resolve inline schema name collisions in the registry

Move duplicate-name handling into mapRegistry.Schema, where type
identity is already tracked via the seen set. Identical inline types
reuse the existing ref (dedup preserved), distinct anonymous types get
a numeric suffix, and named-type collisions still panic. This drops the
NameExistsInSchema addition to the public Registry interface.

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Co-authored-by: mcklmo <m.h98@gx.net>
Co-authored-by: Robert Thomas <31854736+wolveix@users.noreply.github.com>