feat(backend): Abfuellungen und Produkte (Modul 23)

ProductsModule (GET/POST /products, GET/PATCH /products/:id) und
BottlingModule (GET/POST /bottling-batches) mit transaktionaler
Reduzierung der HoneyBatch-Restmenge beim Abfuellen; Ablehnung bei
Abfuellmenge > verfuegbarer Menge. Neue Prisma-Modelle Product und
BottlingBatch (Migration bottling_products).

ApiCore-Backend/prisma/schema.prisma

@@ -49,6 +49,7 @@ model User {
   createdTasks       Task[]                @relation("TaskCreator")
   colonyMoves        ColonyApiaryHistory[]
   auditLogs          AuditLog[]
+  bottlingBatches    BottlingBatch[]
 
   @@index([role])
 }
@@ -528,7 +529,8 @@ model HoneyBatch {
   createdAt          DateTime          @default(now())
   updatedAt          DateTime          @updatedAt
 
-  measurements HoneyMeasurement[]
+  measurements    HoneyMeasurement[]
+  bottlingBatches BottlingBatch[]
 
   @@index([status])
   @@index([extractionId])
@@ -624,3 +626,49 @@ model StockMovement {
 
   @@index([stockItemId, date])
 }
+
+// ---------------------------------------------------------------------------
+// Abfüllungen und Produkte (Abschnitt 4.19, 4.20) – v1.x Modul 23
+// ---------------------------------------------------------------------------
+
+enum ProductStatus {
+  ACTIVE
+  DISCONTINUED
+}
+
+model Product {
+  id             String        @id @default(cuid())
+  name           String
+  description    String?
+  sku            String?       @unique
+  packagingSize  Float?
+  weight         Float?
+  salesUnit      String?
+  status         ProductStatus @default(ACTIVE)
+  createdAt      DateTime      @default(now())
+  updatedAt      DateTime      @updatedAt
+
+  bottlingBatches BottlingBatch[]
+
+  @@index([status])
+}
+
+model BottlingBatch {
+  id             String     @id @default(cuid())
+  honeyBatchId   String
+  honeyBatch     HoneyBatch @relation(fields: [honeyBatchId], references: [id])
+  productId      String?
+  product        Product?   @relation(fields: [productId], references: [id])
+  date           DateTime
+  jarSize        Float
+  jarCount       Int
+  totalAmount    Float
+  bestBeforeDate DateTime
+  lotNumber      String     @unique
+  userId         String?
+  user           User?      @relation(fields: [userId], references: [id])
+  createdAt      DateTime   @default(now())
+
+  @@index([honeyBatchId])
+  @@index([productId])
+}