events: notification delivery flows on lib/flow + 7 tests (Phase 3 start)

notify.sx: reminders + digests as durable flows over an injected transport.
A flow requests delivery (suspend); the host dispatch sends and resumes with
the outcome. At-least-once + idempotent (transport dedups by msg id; replay
logs outcomes). Retry rides suspend/resume with distinct per-attempt tags,
bounded by maxn. Digest delivers a batch with per-message outcomes.
182/182 green. Delivery core is the delivery-on-sx extraction seam.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/events/conformance.conf

@@ -27,6 +27,18 @@ PRELOADS=(
   lib/persist/api.sx
   lib/events/booking.sx
   lib/events/ticket.sx
+  lib/guest/lex.sx
+  lib/guest/reflective/env.sx
+  lib/guest/reflective/quoting.sx
+  lib/scheme/parser.sx
+  lib/scheme/eval.sx
+  lib/scheme/runtime.sx
+  lib/flow/spec.sx
+  lib/flow/store.sx
+  lib/flow/remote.sx
+  lib/flow/host.sx
+  lib/flow/api.sx
+  lib/events/notify.sx
   lib/events/api.sx
 )
 
@@ -36,4 +48,5 @@ SUITES=(
   "api:lib/events/tests/api.sx:(ev-api-tests-run!)"
   "booking:lib/events/tests/booking.sx:(ev-booking-tests-run!)"
   "ticket:lib/events/tests/ticket.sx:(ev-ticket-tests-run!)"
+  "notify:lib/events/tests/notify.sx:(ev-notify-tests-run!)"
 )