scheduleReconnect parks the PTY as "closed" while the tab is hidden or the
chat route is inactive, but left any earlier non-rejection banner (e.g. a
failed image upload) in place. maybeReconnectOnPageResume refuses to
reconnect while a banner sits on a closed PTY and the reconnect overlay
hides behind a banner too, so the tab came back disconnected with no way
to recover. Clear the banner in the deferral branch like the normal
reconnect path does.
Test: hidden-tab 1001 close after a failed upload now opens a second
socket on visibilitychange (1 -> 2), red before the fix.
0dba105b9d