fix(music): don't throw "Transport not connected" while a reconnect is landing

Found live: >5min screen lock while music played, then "Transport not
connected" at the 2nd track's end (~8min in) despite the auto-reconnect
from the previous commit. Root cause: fetchTrackBlob's own
`!transport.connected` pre-flight check ran and threw before the
already-in-progress reconnect got the few seconds it needed — it never
reached _sendAndWait, which is the only place the previous fix taught the
transport to wait.

Adds transport.waitForReconnect(), factored out of _sendAndWait's existing
gate, and calls it from fetchTrackBlob before giving up. No-op when nothing
is being reconnected, so the ordinary path is unchanged.

0 files changed, 0 insertions, 0 deletions