`refreshSubagents` single-flights per catalog owner: a request arriving
while a pull is in flight returns the in-flight promise and is silently
coalesced into it. The in-flight response was requested before the
triggering change, so it can never contain that change — a debounced
membership refresh (50ms after `host/session-added`) firing during a slow
pull therefore lost the new child, and the catalog stayed stale until an
unrelated trigger (reselection, menu reopen, reconnect).
Mark the owner stale on coalescing and re-arm one trailing pull in the
settlement `finally`, so every membership change observed during a pull is
carried by a follow-up refresh exactly once. Bounded: the trailing pull
only runs when a refresh request was actually coalesced, and a new
coalescing during the trailing pull re-marks the same set.
Adds a fake-timer regression test: a `host/session-added` debounce firing
mid-pull yields exactly two `subagent.list` calls and the catalog
eventually contains the new child.
Tianyi Cui
b270b3ef9f