045a0c6379ef4d428a45302fe0c95160d4cea9e8  DOMException should have a stack property, like other errors

Classified as not security-relevant.
Triage note: Replaces finishCreation(StackTraceCapturePolicy) with finishCreationForEmbedderError/setErrorInfoForEmbedderError and serializes error stack info across structured clone, bumping CurrentMajorVersion to 16. This is a feature/behavior change preserving stack info, not a security fix.
This commit was flagged by the signal scorer and reviewed by AI (not a human). It is listed only so the triage is auditable; there is no root-cause analysis because this is not a vulnerability fix.

Structural signals: smartptr_member_added (+4.87), null_guard (+2.59), msg_feature (-1.0), area:Source/JavaScriptCore/runtime (+2.5)