The dispatcher drained a single global FIFO (oldest 20), so one
tenant's billing burst starved every other space's email indefinitely.
Now round-robins an oldest-first candidate window across spaces with a
per-space cap (PER_SPACE=5, BATCH=20). Status writes are guarded with
.eq('status','pending') so an overlapping run can't flip a row another
run already advanced (no false 'failed' on an already-sent row).
Moheeb Zara
c9c0909ad7