feat: add Prisma schema: backend/prisma/schema.prisma

backend/prisma/schema.prisma

@@ -0,0 +1,40 @@
+datasource db {
+  provider = "postgresql"
+}
+
+generator client {
+  provider = "prisma-client"
+}
+
+enum EquipmentStatus {
+  Active
+  Repair
+  Reserve
+  WriteOff
+}
+
+model Equipment {
+  id               String                  @id @default(uuid())
+  name             String
+  serialNumber     String
+  dateOfInspection DateTime?
+  commissionedAt   DateTime?
+  status           EquipmentStatus
+  statusChanges    ChangeEquipmentStatus[]
+  createdAt        DateTime                @default(now())
+  updatedAt        DateTime                @updatedAt
+
+  @@unique([serialNumber])
+}
+
+model ChangeEquipmentStatus {
+  equipmentId String
+  newStatus   EquipmentStatus
+  number      String?
+  date        DateTime
+  responsible String?
+  equipment   Equipment       @relation(fields: [equipmentId], references: [id], onDelete: Cascade)
+
+  @@id([equipmentId, newStatus])
+  @@map("change_equipment_status")
+}