feat(04-01): InventoryService, API routes, migration, and 13 passing tests

- InventoryService: registerItem, recordMovement, getStockLevels, getItemMovements, listItems
- RECEIVED movements auto-post JE (DR 1200 Equipment Inventory, CR 2010 AP)
- Stock levels derived from movement aggregation (no mutable quantity column)
- All 5 movement types validated with type-specific rules
- API routes: POST/GET items, GET item detail, POST/GET movements, GET stock-levels
- CASL: OFFICE_STAFF gets manage Inventory permission
- Migration applied: add_inventory_models (4 enums, 2 tables)
- 13 tests: registration, all movement types, stock derivation, JE posting, history

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

prisma/migrations/20260305021700_add_inventory_models/migration.sql

@@ -0,0 +1,77 @@
+-- CreateEnum
+CREATE TYPE "ItemTrackingType" AS ENUM ('SERIALIZED', 'BATCH');
+
+-- CreateEnum
+CREATE TYPE "ItemCondition" AS ENUM ('NEW', 'REFURBISHED', 'USED', 'DAMAGED');
+
+-- CreateEnum
+CREATE TYPE "MovementType" AS ENUM ('RECEIVED', 'ISSUED', 'RETURNED', 'DISPOSED', 'TRANSFERRED');
+
+-- CreateEnum
+CREATE TYPE "LocationType" AS ENUM ('WAREHOUSE', 'TECHNICIAN', 'SUBSCRIBER');
+
+-- CreateTable
+CREATE TABLE "InventoryItem" (
+    "id" TEXT NOT NULL,
+    "tenantId" TEXT NOT NULL,
+    "name" TEXT NOT NULL,
+    "itemType" TEXT NOT NULL,
+    "model" TEXT,
+    "serialNumber" TEXT,
+    "trackingType" "ItemTrackingType" NOT NULL,
+    "purchaseCost" DECIMAL(10,2),
+    "purchaseDate" TIMESTAMP(3),
+    "warrantyExpiry" TIMESTAMP(3),
+    "isActive" BOOLEAN NOT NULL DEFAULT true,
+    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "updatedAt" TIMESTAMP(3) NOT NULL,
+
+    CONSTRAINT "InventoryItem_pkey" PRIMARY KEY ("id")
+);
+
+-- CreateTable
+CREATE TABLE "StockMovement" (
+    "id" TEXT NOT NULL,
+    "tenantId" TEXT NOT NULL,
+    "inventoryItemId" TEXT NOT NULL,
+    "movementType" "MovementType" NOT NULL,
+    "quantity" INTEGER NOT NULL DEFAULT 1,
+    "condition" "ItemCondition",
+    "fromLocationType" "LocationType",
+    "fromLocationId" TEXT,
+    "toLocationType" "LocationType",
+    "toLocationId" TEXT,
+    "notes" TEXT,
+    "journalEntryId" TEXT,
+    "performedById" TEXT NOT NULL,
+    "createdAt" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+
+    CONSTRAINT "StockMovement_pkey" PRIMARY KEY ("id")
+);
+
+-- CreateIndex
+CREATE INDEX "InventoryItem_tenantId_idx" ON "InventoryItem"("tenantId");
+
+-- CreateIndex
+CREATE INDEX "InventoryItem_tenantId_itemType_idx" ON "InventoryItem"("tenantId", "itemType");
+
+-- CreateIndex
+CREATE INDEX "InventoryItem_tenantId_trackingType_idx" ON "InventoryItem"("tenantId", "trackingType");
+
+-- CreateIndex
+CREATE UNIQUE INDEX "InventoryItem_tenantId_serialNumber_key" ON "InventoryItem"("tenantId", "serialNumber");
+
+-- CreateIndex
+CREATE INDEX "StockMovement_tenantId_idx" ON "StockMovement"("tenantId");
+
+-- CreateIndex
+CREATE INDEX "StockMovement_inventoryItemId_idx" ON "StockMovement"("inventoryItemId");
+
+-- CreateIndex
+CREATE INDEX "StockMovement_tenantId_movementType_idx" ON "StockMovement"("tenantId", "movementType");
+
+-- AddForeignKey
+ALTER TABLE "StockMovement" ADD CONSTRAINT "StockMovement_inventoryItemId_fkey" FOREIGN KEY ("inventoryItemId") REFERENCES "InventoryItem"("id") ON DELETE RESTRICT ON UPDATE CASCADE;
+
+-- AddForeignKey
+ALTER TABLE "StockMovement" ADD CONSTRAINT "StockMovement_performedById_fkey" FOREIGN KEY ("performedById") REFERENCES "User"("id") ON DELETE RESTRICT ON UPDATE CASCADE;