The previous reset dropped #pendingXdevMountDelta alongside the announced
baseline. Unlike /new and different-session switchSession, branch() does
not rebuild the base system prompt afterward, and because the device is
already in mountedNames no later refresh re-queues an add delta. Dropping
the undelivered delta therefore left the branched transcript unaware of a
still-mounted discoverable device.
Only the announced baseline is reset now; pending adds (still-live mounts
awaiting delivery) survive and announce on the next prompt in the new
transcript. Redundant on /new (the rebuilt prompt lists them too) but
harmless, and correct for branch.
Fixes#6921
(cherry picked from commit 5866440f27c15a320657e25fbfa0d2d65aad1fa2)
roboomp
359dfb5b8f