ev/deliver-messages bridges SX notification messages to the Scheme notify
flow: each (id recipient body) is serialized to s-expr text, spliced as quoted
data into the digest-flow program, delivered over an injected transport, and
results unboxed. Integration suite drives all three derivations (reminders /
booking-notify / reschedule) through delivery end to end; empty batch guarded
(empty digest completes without suspending). 303/303 green.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>