feat: add MaintenanceRecord Prisma model + migration

New entity tracking repair/warranty/preventive maintenance jobs for an
AssetItem. Reuses Vendor (nullable) for the repair location, no cost
field (mirrors PurchaseOrder). "At most 1 open record per AssetItem"
invariant left to the application layer, mirroring Assignment.

prisma/migrations/20260804092355_add_maintenance_record/migration.sql

@@ -0,0 +1,23 @@
+-- CreateEnum
+CREATE TYPE "MaintenanceType" AS ENUM ('repair', 'warranty', 'preventive');
+
+-- CreateTable
+CREATE TABLE "maintenance_records" (
+    "id" UUID NOT NULL,
+    "asset_item_id" UUID NOT NULL,
+    "type" "MaintenanceType" NOT NULL,
+    "vendor_id" UUID,
+    "issue_description" TEXT NOT NULL,
+    "resolution_notes" TEXT,
+    "start_date" DATE NOT NULL,
+    "end_date" DATE,
+    "created_at" TIMESTAMPTZ(6) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+
+    CONSTRAINT "maintenance_records_pkey" PRIMARY KEY ("id")
+);
+
+-- AddForeignKey
+ALTER TABLE "maintenance_records" ADD CONSTRAINT "maintenance_records_asset_item_id_fkey" FOREIGN KEY ("asset_item_id") REFERENCES "asset_items"("id") ON DELETE RESTRICT ON UPDATE CASCADE;
+
+-- AddForeignKey
+ALTER TABLE "maintenance_records" ADD CONSTRAINT "maintenance_records_vendor_id_fkey" FOREIGN KEY ("vendor_id") REFERENCES "vendors"("id") ON DELETE SET NULL ON UPDATE CASCADE;

prisma/schema.prisma

@@ -125,6 +125,11 @@ model AssetItem {
   // multiple Assignment rows over its lifetime (historical + at most one
   // active, see Assignment model's comment), not built until this task.
   assignments        Assignment[]
+  // Back-relation for MaintenanceRecord.assetItemId — an AssetItem can have
+  // multiple MaintenanceRecord rows over its lifetime (historical + at most
+  // one open, see MaintenanceRecord model's comment), not built until this
+  // task.
+  maintenanceRecords MaintenanceRecord[]
 
   @@map("asset_items")
 }
@@ -194,6 +199,10 @@ model Vendor {
   createdAt          DateTime             @default(now()) @map("created_at") @db.Timestamptz(6)
   licenses           License[]
   purchaseOrders     PurchaseOrder[]
+  // Back-relation for MaintenanceRecord.vendorId — a Vendor can perform
+  // multiple repairs/warranty jobs over time, same reuse rationale as
+  // PurchaseOrder.vendorId (see MaintenanceRecord model's comment).
+  maintenanceRecords MaintenanceRecord[]
 
   @@map("vendors")
 }
@@ -417,3 +426,50 @@ model User {
 
   @@map("users")
 }
+
+// Fixed, closed set of 3 values tied to the domain (see docs/
+// asset-license-management.md's "## MaintenanceRecord (spec BA + stakeholder,
+// chốt 2026-08-04)" section) — native Postgres enum, same rationale as
+// RequestType/AssetItemStatus/LicenseType/AssetCategoryValueGroup/
+// AssetAttributeDataType above.
+enum MaintenanceType {
+  repair
+  warranty
+  preventive
+}
+
+// Records a repair/warranty/preventive-maintenance job for a specific
+// AssetItem — see docs/asset-license-management.md's "## MaintenanceRecord
+// (spec BA + stakeholder, chốt 2026-08-04)" section. Only applies to
+// AssetItem (hardware) — License has no physical-repair concept, so unlike
+// Assignment there's no XOR here: assetItemId is the single, always-required
+// target. `vendorId` reuses the existing Vendor entity (same "external
+// counterparty" concept as PurchaseOrder.vendorId) and is nullable — null
+// means an internal repair with no outside vendor involved. No `cost` field,
+// per the same precedent as PurchaseOrder (stakeholder explicitly said no
+// money tracking there). No separate `status` field either — "open" vs
+// "done" is derived from `endDate` (null = still being worked on, set = done),
+// same precedent as PurchaseOrder.receivedAt not duplicating state. `endDate
+// >= startDate` and "at most one OPEN (endDate IS NULL) MaintenanceRecord per
+// AssetItem" are both business invariants enforced at the application layer
+// (src/lib/maintenance-records.ts, not built in this task) — NOT DB
+// constraints, per the same convention as Assignment's XOR / "at most one
+// active" invariant (see Assignment model's comment above for the mirrored
+// trade-off). No FK to User for "who logged this" — no existing precedent in
+// this codebase ties a business entity to User (User is login-only), see
+// doc for this explicit call.
+model MaintenanceRecord {
+  id               String           @id @default(uuid()) @db.Uuid
+  assetItemId      String           @map("asset_item_id") @db.Uuid
+  assetItem        AssetItem        @relation(fields: [assetItemId], references: [id])
+  type             MaintenanceType
+  vendorId         String?          @map("vendor_id") @db.Uuid
+  vendor           Vendor?          @relation(fields: [vendorId], references: [id])
+  issueDescription String           @map("issue_description")
+  resolutionNotes  String?          @map("resolution_notes")
+  startDate        DateTime         @map("start_date") @db.Date
+  endDate          DateTime?        @map("end_date") @db.Date
+  createdAt        DateTime         @default(now()) @map("created_at") @db.Timestamptz(6)
+
+  @@map("maintenance_records")
+}