feat: remediate HTTP API reliability and developer documentation

api/prisma/migrations/20260914060000_http_api_durable_delivery/migration.sql

@@ -0,0 +1,11 @@
+ALTER TABLE "HttpWebhookDelivery" ADD COLUMN "recoveryVersion" INTEGER NOT NULL DEFAULT 0,
+ADD COLUMN "leaseToken" TEXT, ADD COLUMN "leaseUntil" TIMESTAMP(3);
+CREATE TABLE "OpenApiDispatchOutbox" (
+  "id" TEXT NOT NULL, "requestId" TEXT NOT NULL, "batchTaskId" TEXT NOT NULL,
+  "status" TEXT NOT NULL DEFAULT 'pending', "leaseToken" TEXT, "leaseUntil" TIMESTAMP(3),
+  "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP, "updatedAt" TIMESTAMP(3) NOT NULL,
+  CONSTRAINT "OpenApiDispatchOutbox_pkey" PRIMARY KEY ("id")
+);
+CREATE UNIQUE INDEX "OpenApiDispatchOutbox_requestId_key" ON "OpenApiDispatchOutbox"("requestId");
+CREATE UNIQUE INDEX "OpenApiDispatchOutbox_batchTaskId_key" ON "OpenApiDispatchOutbox"("batchTaskId");
+CREATE INDEX "OpenApiDispatchOutbox_status_leaseUntil_idx" ON "OpenApiDispatchOutbox"("status", "leaseUntil");

api/prisma/schema.prisma

@@ -686,6 +686,9 @@ model HttpWebhookEvent {
 }
 
 model HttpWebhookDelivery {
+  recoveryVersion Int @default(0)
+  leaseToken String?
+  leaseUntil DateTime?
   id             String    @id @default(cuid())
   eventId        String
   endpointId     String
@@ -2825,3 +2828,15 @@ model SendingMonitorTargetVersion {
   updatedBy String
   @@id([channelId,version])
 }
+
+model OpenApiDispatchOutbox {
+  id String @id @default(cuid())
+  requestId String @unique
+  batchTaskId String @unique
+  status String @default("pending")
+  leaseToken String?
+  leaseUntil DateTime?
+  createdAt DateTime @default(now())
+  updatedAt DateTime @updatedAt
+  @@index([status, leaseUntil])
+}