9f9aae3434d37674484277936178e57a9086eae0  [JSC] WASM debugger: report an interrupt at a wasm prologue as a real stop

Classified as not security-relevant.
Triage note: setStepBreakpoint becomes templated setOneTimeBreakpoint<reason> supporting Step/Interrupted and handles interrupt-at-prologue; wasm debug-server (LLDB) feature, not a web-reachable surface.
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 (+3.0), security_assert (+4.87)