fix(production): JPA-Save-Pattern, Optimistic Locking und Domain-Validierung

- Managed-Entity-Update statt detach/merge (verhindert DELETE+INSERT-Churn)
- @Version für Optimistic Locking mit ConcurrentModification-Error
- Null-Checks für quantityUsed/quantityUnit vor BigDecimal-Parsing
- Duplicate-Check nach Consumption.create() für robustere Validierung
- FetchType.EAGER→LAZY für BatchEntity.consumptions
- Liquibase-Migration 020 für version-Spalte

backend/src/test/java/de/effigenix/application/production/FindBatchByNumberTest.java

@@ -53,7 +53,7 @@ class FindBatchByNumberTest {
                 LocalDate.of(2026, 6, 1),
                 OffsetDateTime.now(ZoneOffset.UTC),
                 OffsetDateTime.now(ZoneOffset.UTC),
-                List.of()
+                0L, List.of()
         );
     }
 

backend/src/test/java/de/effigenix/application/production/GetBatchTest.java

@@ -51,7 +51,7 @@ class GetBatchTest {
                 LocalDate.of(2026, 6, 1),
                 OffsetDateTime.now(ZoneOffset.UTC),
                 OffsetDateTime.now(ZoneOffset.UTC),
-                List.of()
+                0L, List.of()
         );
     }
 

backend/src/test/java/de/effigenix/application/production/ListBatchesTest.java

@@ -55,7 +55,7 @@ class ListBatchesTest {
                 LocalDate.of(2026, 6, 1),
                 OffsetDateTime.now(ZoneOffset.UTC),
                 OffsetDateTime.now(ZoneOffset.UTC),
-                List.of()
+                0L, List.of()
         );
     }
 

backend/src/test/java/de/effigenix/application/production/RecordConsumptionTest.java

@@ -52,7 +52,7 @@ class RecordConsumptionTest {
                 LocalDate.of(2026, 6, 1),
                 OffsetDateTime.now(ZoneOffset.UTC),
                 OffsetDateTime.now(ZoneOffset.UTC),
-                List.of()
+                0L, List.of()
         );
     }
 
@@ -67,7 +67,7 @@ class RecordConsumptionTest {
                 LocalDate.of(2026, 6, 1),
                 OffsetDateTime.now(ZoneOffset.UTC),
                 OffsetDateTime.now(ZoneOffset.UTC),
-                List.of()
+                0L, List.of()
         );
     }
 

backend/src/test/java/de/effigenix/application/production/StartBatchTest.java

@@ -52,7 +52,7 @@ class StartBatchTest {
                 LocalDate.of(2026, 6, 1),
                 OffsetDateTime.now(ZoneOffset.UTC),
                 OffsetDateTime.now(ZoneOffset.UTC),
-                List.of()
+                0L, List.of()
         );
     }
 
@@ -67,7 +67,7 @@ class StartBatchTest {
                 LocalDate.of(2026, 6, 1),
                 OffsetDateTime.now(ZoneOffset.UTC),
                 OffsetDateTime.now(ZoneOffset.UTC),
-                List.of()
+                0L, List.of()
         );
     }
 

backend/src/test/java/de/effigenix/domain/production/BatchTest.java

@@ -210,7 +210,7 @@ class BatchTest {
                     Quantity.of(new BigDecimal("100"), UnitOfMeasure.KILOGRAM).unsafeGetValue(),
                     PRODUCTION_DATE, BEST_BEFORE_DATE,
                     OffsetDateTime.now(ZoneOffset.UTC), OffsetDateTime.now(ZoneOffset.UTC),
-                    List.of()
+                    0L, List.of()
             );
 
             var result = batch.startProduction();
@@ -231,7 +231,7 @@ class BatchTest {
                     Quantity.of(new BigDecimal("100"), UnitOfMeasure.KILOGRAM).unsafeGetValue(),
                     PRODUCTION_DATE, BEST_BEFORE_DATE,
                     OffsetDateTime.now(ZoneOffset.UTC), OffsetDateTime.now(ZoneOffset.UTC),
-                    List.of()
+                    0L, List.of()
             );
 
             var result = batch.startProduction();
@@ -249,7 +249,7 @@ class BatchTest {
                     Quantity.of(new BigDecimal("100"), UnitOfMeasure.KILOGRAM).unsafeGetValue(),
                     PRODUCTION_DATE, BEST_BEFORE_DATE,
                     OffsetDateTime.now(ZoneOffset.UTC), OffsetDateTime.now(ZoneOffset.UTC),
-                    List.of()
+                    0L, List.of()
             );
 
             var result = batch.startProduction();
@@ -313,7 +313,7 @@ class BatchTest {
                     Quantity.of(new BigDecimal("100"), UnitOfMeasure.KILOGRAM).unsafeGetValue(),
                     PRODUCTION_DATE, BEST_BEFORE_DATE,
                     OffsetDateTime.now(ZoneOffset.UTC), OffsetDateTime.now(ZoneOffset.UTC),
-                    List.of()
+                    0L, List.of()
             );
             var draft = new ConsumptionDraft("input-1", "article-1", "5.0", "KILOGRAM");
 
@@ -379,7 +379,7 @@ class BatchTest {
                     BEST_BEFORE_DATE,
                     OffsetDateTime.now(ZoneOffset.UTC),
                     OffsetDateTime.now(ZoneOffset.UTC),
-                    List.of()
+                    0L, List.of()
             );
 
             assertThat(batch.id().value()).isEqualTo("batch-1");

backend/src/test/java/de/effigenix/domain/production/ConsumptionTest.java

@@ -111,6 +111,28 @@ class ConsumptionTest {
             assertThat(result.unsafeGetError()).isInstanceOf(BatchError.InvalidConsumptionQuantity.class);
         }
 
+        @Test
+        @DisplayName("should fail when quantity is null")
+        void should_Fail_When_QuantityNull() {
+            var draft = new ConsumptionDraft("input-batch-1", "article-1", null, "KILOGRAM");
+
+            var result = Consumption.create(draft);
+
+            assertThat(result.isFailure()).isTrue();
+            assertThat(result.unsafeGetError()).isInstanceOf(BatchError.InvalidConsumptionQuantity.class);
+        }
+
+        @Test
+        @DisplayName("should fail when unit is null")
+        void should_Fail_When_UnitNull() {
+            var draft = new ConsumptionDraft("input-batch-1", "article-1", "10", null);
+
+            var result = Consumption.create(draft);
+
+            assertThat(result.isFailure()).isTrue();
+            assertThat(result.unsafeGetError()).isInstanceOf(BatchError.InvalidConsumptionQuantity.class);
+        }
+
         @Test
         @DisplayName("should fail when unit is invalid")
         void should_Fail_When_UnitInvalid() {