fix: harden admin and CMPP delivery workflows

api/prisma/migrations/20260715090000_track_downstream_manual_retries/migration.sql

@@ -0,0 +1,3 @@
+ALTER TABLE "CmppDownstreamDelivery"
+  ADD COLUMN "manualRetryCount" INTEGER NOT NULL DEFAULT 0,
+  ADD COLUMN "lastRetriedAt" TIMESTAMP(3);

api/prisma/migrations/20260715153000_remove_disconnected_downstream_sessions/migration.sql

@@ -0,0 +1,4 @@
+-- Downstream connection rows represent current live sessions only.
+-- Remove historical disconnected/timeout rows left by the previous persistence model.
+DELETE FROM "CmppDownstreamConnection"
+WHERE "status" <> 'connected';

api/prisma/schema.prisma

@@ -1197,6 +1197,8 @@ model CmppDownstreamDelivery {
   payload         Json
   retryEnabled    Boolean  @default(true)
   retryCount      Int      @default(0)
+  manualRetryCount Int     @default(0)
+  lastRetriedAt   DateTime?
   nextRetryAt     DateTime?
   sentAt          DateTime?
   acknowledgedAt  DateTime?