feat(P17B-1,P17B-2): 补齐采购预算闭环与归档模型接口

server/prisma/migrations/20260307131616_p17b_procurement_budget_archive/migration.sql

@@ -0,0 +1,27 @@
+-- CreateTable
+CREATE TABLE "purchase_order_archives" (
+    "id" UUID NOT NULL,
+    "purchase_request_id" UUID NOT NULL,
+    "po_no" TEXT NOT NULL,
+    "contract_no" TEXT,
+    "archived_files" JSONB,
+    "archived_at" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "archived_by" UUID NOT NULL,
+
+    CONSTRAINT "purchase_order_archives_pkey" PRIMARY KEY ("id")
+);
+
+-- CreateIndex
+CREATE UNIQUE INDEX "purchase_order_archives_purchase_request_id_key" ON "purchase_order_archives"("purchase_request_id");
+
+-- CreateIndex
+CREATE INDEX "idx_purchase_order_archives_archived_by" ON "purchase_order_archives"("archived_by");
+
+-- CreateIndex
+CREATE INDEX "idx_purchase_order_archives_archived_at" ON "purchase_order_archives"("archived_at");
+
+-- AddForeignKey
+ALTER TABLE "purchase_order_archives" ADD CONSTRAINT "purchase_order_archives_purchase_request_id_fkey" FOREIGN KEY ("purchase_request_id") REFERENCES "purchase_requests"("id") ON DELETE CASCADE ON UPDATE CASCADE;
+
+-- AddForeignKey
+ALTER TABLE "purchase_order_archives" ADD CONSTRAINT "purchase_order_archives_archived_by_fkey" FOREIGN KEY ("archived_by") REFERENCES "employees"("id") ON DELETE RESTRICT ON UPDATE CASCADE;