Dereference nested effect scopes on manual stop

Editor assessment

Technically excellent subject, sparsely documented. 'dereference nested effect scopes on manual stop' is imperative, precise, and tells a reactivity-savvy reader exactly what leak was plugged — nested scopes lingering after an explicit stop. fix(reactivity) is the right classification, and the header is comfortably short. What is missing is any body: no issue number, no explanation of the retention path or how to reproduce it. Memory-leak fixes especially benefit from that narrative, both for future maintainers and for changelog tooling that will surface this fix to users debugging similar leaks. Strong header, thin record overall.