Refs #4467.
Retain failed socket owners across translated failures and resolve aggregate cleanup only after every required transport closes. Preserve concurrently active peer sessions.
Own CDP transports from admission through observed close, retain failed
owners for retry, and keep active peers separate from pending cleanup.
Preserve primary errors and completed facts through final cancellation.
Forward passive Electron CLI cancellation and dispose browser, runtime and
scenario owners from CLI and MCP shutdown.
Refs #4255, #4256, #4257
morluto