feat(inventory): Bestandsposition anlegen (#4)

Stock-Aggregate mit MinimumLevel, MinimumShelfLife und StockDraft.
Quantity/UnitOfMeasure nach shared.common verschoben für BC-übergreifende
Nutzung. REST-Endpoint POST /api/inventory/stocks mit Duplikat-Prüfung,
Validierung und Liquibase-Migration.

backend/src/main/java/de/effigenix/application/inventory/CreateStock.java

@@ -0,0 +1,59 @@
+package de.effigenix.application.inventory;
+
+import de.effigenix.application.inventory.command.CreateStockCommand;
+import de.effigenix.domain.inventory.*;
+import de.effigenix.shared.common.RepositoryError;
+import de.effigenix.shared.common.Result;
+import org.springframework.transaction.annotation.Transactional;
+
+@Transactional
+public class CreateStock {
+
+    private final StockRepository stockRepository;
+
+    public CreateStock(StockRepository stockRepository) {
+        this.stockRepository = stockRepository;
+    }
+
+    public Result<StockError, Stock> execute(CreateStockCommand cmd) {
+        // 1. Draft aus Command bauen (kein VO-Wissen im Use Case)
+        var draft = new StockDraft(
+                cmd.articleId(), cmd.storageLocationId(),
+                cmd.minimumLevelAmount(), cmd.minimumLevelUnit(),
+                cmd.minimumShelfLifeDays()
+        );
+
+        // 2. Aggregate erzeugen (validiert intern)
+        Stock stock;
+        switch (Stock.create(draft)) {
+            case Result.Failure(var err) -> { return Result.failure(err); }
+            case Result.Success(var val) -> stock = val;
+        }
+
+        // 3. Uniqueness-Check (Application-Concern: braucht Repository)
+        switch (stockRepository.existsByArticleIdAndStorageLocationId(stock.articleId(), stock.storageLocationId())) {
+            case Result.Failure(var err) ->
+                    { return Result.failure(new StockError.RepositoryFailure(err.message())); }
+            case Result.Success(var exists) -> {
+                if (exists) {
+                    return Result.failure(new StockError.DuplicateStock(
+                            cmd.articleId(), cmd.storageLocationId()));
+                }
+            }
+        }
+
+        // 4. Speichern (Race-Condition-Schutz: DuplicateEntry → DuplicateStock)
+        switch (stockRepository.save(stock)) {
+            case Result.Failure(var err) -> {
+                if (err instanceof RepositoryError.DuplicateEntry) {
+                    return Result.failure(new StockError.DuplicateStock(
+                            cmd.articleId(), cmd.storageLocationId()));
+                }
+                return Result.failure(new StockError.RepositoryFailure(err.message()));
+            }
+            case Result.Success(var ignored) -> { }
+        }
+
+        return Result.success(stock);
+    }
+}

backend/src/main/java/de/effigenix/application/inventory/command/CreateStockCommand.java

@@ -0,0 +1,9 @@
+package de.effigenix.application.inventory.command;
+
+public record CreateStockCommand(
+        String articleId,
+        String storageLocationId,
+        String minimumLevelAmount,
+        String minimumLevelUnit,
+        Integer minimumShelfLifeDays
+) {}

backend/src/main/java/de/effigenix/domain/inventory/MinimumLevel.java

@@ -0,0 +1,47 @@
+package de.effigenix.domain.inventory;
+
+import de.effigenix.shared.common.Quantity;
+import de.effigenix.shared.common.Result;
+import de.effigenix.shared.common.UnitOfMeasure;
+
+import java.math.BigDecimal;
+
+public record MinimumLevel(Quantity quantity) {
+
+    public static Result<StockError, MinimumLevel> of(String amount, String unit) {
+        if (amount == null || amount.isBlank()) {
+            return Result.failure(new StockError.InvalidMinimumLevel("amount must not be blank"));
+        }
+        if (unit == null || unit.isBlank()) {
+            return Result.failure(new StockError.InvalidMinimumLevel("unit must not be blank"));
+        }
+
+        BigDecimal parsedAmount;
+        try {
+            parsedAmount = new BigDecimal(amount);
+        } catch (NumberFormatException e) {
+            return Result.failure(new StockError.InvalidMinimumLevel("amount is not a valid number: " + amount));
+        }
+
+        if (parsedAmount.compareTo(BigDecimal.ZERO) < 0) {
+            return Result.failure(new StockError.InvalidMinimumLevel("amount must be >= 0, was: " + amount));
+        }
+
+        UnitOfMeasure parsedUnit;
+        try {
+            parsedUnit = UnitOfMeasure.valueOf(unit);
+        } catch (IllegalArgumentException e) {
+            return Result.failure(new StockError.InvalidMinimumLevel("invalid unit: " + unit));
+        }
+
+        // MinimumLevel erlaubt amount == 0 (kein Mindestbestand)
+        // Quantity.of() verlangt amount > 0, daher Reconstitute verwenden
+        if (parsedAmount.compareTo(BigDecimal.ZERO) == 0) {
+            return Result.success(new MinimumLevel(Quantity.reconstitute(parsedAmount, parsedUnit, null, null)));
+        }
+
+        return Quantity.of(parsedAmount, parsedUnit)
+                .map(MinimumLevel::new)
+                .mapError(qErr -> new StockError.InvalidMinimumLevel(qErr.message()));
+    }
+}

backend/src/main/java/de/effigenix/domain/inventory/MinimumShelfLife.java

@@ -0,0 +1,13 @@
+package de.effigenix.domain.inventory;
+
+import de.effigenix.shared.common.Result;
+
+public record MinimumShelfLife(int days) {
+
+    public static Result<StockError, MinimumShelfLife> of(Integer days) {
+        if (days == null || days <= 0) {
+            return Result.failure(new StockError.InvalidMinimumShelfLife(days == null ? 0 : days));
+        }
+        return Result.success(new MinimumShelfLife(days));
+    }
+}

backend/src/main/java/de/effigenix/domain/inventory/Stock.java

@@ -0,0 +1,125 @@
+package de.effigenix.domain.inventory;
+
+import de.effigenix.domain.masterdata.ArticleId;
+import de.effigenix.shared.common.Result;
+
+import java.util.Objects;
+
+/**
+ * Stock aggregate root.
+ *
+ * Invariants:
+ * - ArticleId + StorageLocationId = unique (Application Layer, Repository-Concern)
+ * - MinimumLevel optional (quantity amount >= 0)
+ * - MinimumShelfLife optional (days > 0)
+ */
+public class Stock {
+
+    private final StockId id;
+    private final ArticleId articleId;
+    private final StorageLocationId storageLocationId;
+    private MinimumLevel minimumLevel;
+    private MinimumShelfLife minimumShelfLife;
+
+    private Stock(
+            StockId id,
+            ArticleId articleId,
+            StorageLocationId storageLocationId,
+            MinimumLevel minimumLevel,
+            MinimumShelfLife minimumShelfLife
+    ) {
+        this.id = id;
+        this.articleId = articleId;
+        this.storageLocationId = storageLocationId;
+        this.minimumLevel = minimumLevel;
+        this.minimumShelfLife = minimumShelfLife;
+    }
+
+    /**
+     * Factory: Erzeugt ein neues Stock-Aggregat aus rohen Eingaben.
+     * Orchestriert Validierung aller VOs intern.
+     */
+    public static Result<StockError, Stock> create(StockDraft draft) {
+        // 1. ArticleId validieren (Pflicht)
+        if (draft.articleId() == null || draft.articleId().isBlank()) {
+            return Result.failure(new StockError.InvalidArticleId("must not be blank"));
+        }
+        ArticleId articleId;
+        try {
+            articleId = ArticleId.of(draft.articleId());
+        } catch (IllegalArgumentException e) {
+            return Result.failure(new StockError.InvalidArticleId(e.getMessage()));
+        }
+
+        // 2. StorageLocationId validieren (Pflicht)
+        if (draft.storageLocationId() == null || draft.storageLocationId().isBlank()) {
+            return Result.failure(new StockError.InvalidStorageLocationId("must not be blank"));
+        }
+        StorageLocationId storageLocationId;
+        try {
+            storageLocationId = StorageLocationId.of(draft.storageLocationId());
+        } catch (IllegalArgumentException e) {
+            return Result.failure(new StockError.InvalidStorageLocationId(e.getMessage()));
+        }
+
+        // 3. MinimumLevel optional
+        MinimumLevel minimumLevel = null;
+        if (draft.minimumLevelAmount() != null || draft.minimumLevelUnit() != null) {
+            switch (MinimumLevel.of(draft.minimumLevelAmount(), draft.minimumLevelUnit())) {
+                case Result.Failure(var err) -> { return Result.failure(err); }
+                case Result.Success(var val) -> minimumLevel = val;
+            }
+        }
+
+        // 4. MinimumShelfLife optional
+        MinimumShelfLife minimumShelfLife = null;
+        if (draft.minimumShelfLifeDays() != null) {
+            switch (MinimumShelfLife.of(draft.minimumShelfLifeDays())) {
+                case Result.Failure(var err) -> { return Result.failure(err); }
+                case Result.Success(var val) -> minimumShelfLife = val;
+            }
+        }
+
+        return Result.success(new Stock(
+                StockId.generate(), articleId, storageLocationId, minimumLevel, minimumShelfLife
+        ));
+    }
+
+    /**
+     * Reconstitute from persistence without re-validation.
+     */
+    public static Stock reconstitute(
+            StockId id,
+            ArticleId articleId,
+            StorageLocationId storageLocationId,
+            MinimumLevel minimumLevel,
+            MinimumShelfLife minimumShelfLife
+    ) {
+        return new Stock(id, articleId, storageLocationId, minimumLevel, minimumShelfLife);
+    }
+
+    // ==================== Getters ====================
+
+    public StockId id() { return id; }
+    public ArticleId articleId() { return articleId; }
+    public StorageLocationId storageLocationId() { return storageLocationId; }
+    public MinimumLevel minimumLevel() { return minimumLevel; }
+    public MinimumShelfLife minimumShelfLife() { return minimumShelfLife; }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (!(obj instanceof Stock other)) return false;
+        return Objects.equals(id, other.id);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(id);
+    }
+
+    @Override
+    public String toString() {
+        return "Stock{id=" + id + ", articleId=" + articleId + ", storageLocationId=" + storageLocationId + "}";
+    }
+}

backend/src/main/java/de/effigenix/domain/inventory/StockDraft.java

@@ -0,0 +1,20 @@
+package de.effigenix.domain.inventory;
+
+/**
+ * Rohe Eingabe zum Erzeugen eines Stock-Aggregates.
+ * Wird vom Application Layer aus dem Command gebaut und an Stock.create() übergeben.
+ * Das Aggregate ist verantwortlich für Validierung und VO-Konstruktion.
+ *
+ * @param articleId              Pflicht
+ * @param storageLocationId      Pflicht
+ * @param minimumLevelAmount     Optional – BigDecimal als String, nullable
+ * @param minimumLevelUnit       Optional – UnitOfMeasure als String, nullable
+ * @param minimumShelfLifeDays   Optional – Integer, nullable
+ */
+public record StockDraft(
+        String articleId,
+        String storageLocationId,
+        String minimumLevelAmount,
+        String minimumLevelUnit,
+        Integer minimumShelfLifeDays
+) {}

backend/src/main/java/de/effigenix/domain/inventory/StockError.java

@@ -0,0 +1,45 @@
+package de.effigenix.domain.inventory;
+
+public sealed interface StockError {
+
+    String code();
+    String message();
+
+    record DuplicateStock(String articleId, String storageLocationId) implements StockError {
+        @Override public String code() { return "DUPLICATE_STOCK"; }
+        @Override public String message() { return "Stock already exists for article " + articleId + " at location " + storageLocationId; }
+    }
+
+    record InvalidMinimumLevel(String reason) implements StockError {
+        @Override public String code() { return "INVALID_MINIMUM_LEVEL"; }
+        @Override public String message() { return "Invalid minimum level: " + reason; }
+    }
+
+    record InvalidMinimumShelfLife(int days) implements StockError {
+        @Override public String code() { return "INVALID_MINIMUM_SHELF_LIFE"; }
+        @Override public String message() { return "Minimum shelf life must be > 0, was: " + days; }
+    }
+
+    record StockNotFound(String id) implements StockError {
+        @Override public String code() { return "STOCK_NOT_FOUND"; }
+        @Override public String message() { return "Stock not found: " + id; }
+    }
+
+    record InvalidArticleId(String reason) implements StockError {
+        @Override public String code() { return "INVALID_ARTICLE_ID"; }
+        @Override public String message() { return "Invalid article ID: " + reason; }
+    }
+
+    record InvalidStorageLocationId(String reason) implements StockError {
+        @Override public String code() { return "INVALID_STORAGE_LOCATION_ID"; }
+        @Override public String message() { return "Invalid storage location ID: " + reason; }
+    }
+
+    record Unauthorized(String message) implements StockError {
+        @Override public String code() { return "UNAUTHORIZED"; }
+    }
+
+    record RepositoryFailure(String message) implements StockError {
+        @Override public String code() { return "REPOSITORY_ERROR"; }
+    }
+}

backend/src/main/java/de/effigenix/domain/inventory/StockId.java

@@ -0,0 +1,20 @@
+package de.effigenix.domain.inventory;
+
+import java.util.UUID;
+
+public record StockId(String value) {
+
+    public StockId {
+        if (value == null || value.isBlank()) {
+            throw new IllegalArgumentException("StockId must not be blank");
+        }
+    }
+
+    public static StockId generate() {
+        return new StockId(UUID.randomUUID().toString());
+    }
+
+    public static StockId of(String value) {
+        return new StockId(value);
+    }
+}

backend/src/main/java/de/effigenix/domain/inventory/StockRepository.java

@@ -0,0 +1,18 @@
+package de.effigenix.domain.inventory;
+
+import de.effigenix.domain.masterdata.ArticleId;
+import de.effigenix.shared.common.RepositoryError;
+import de.effigenix.shared.common.Result;
+
+import java.util.Optional;
+
+public interface StockRepository {
+
+    Result<RepositoryError, Optional<Stock>> findById(StockId id);
+
+    Result<RepositoryError, Optional<Stock>> findByArticleIdAndStorageLocationId(ArticleId articleId, StorageLocationId storageLocationId);
+
+    Result<RepositoryError, Boolean> existsByArticleIdAndStorageLocationId(ArticleId articleId, StorageLocationId storageLocationId);
+
+    Result<RepositoryError, Void> save(Stock stock);
+}

backend/src/main/java/de/effigenix/domain/production/BatchNumber.java

@@ -1,5 +1,6 @@
 package de.effigenix.domain.production;
 
+import de.effigenix.shared.common.QuantityError;
 import de.effigenix.shared.common.Result;
 
 import java.time.LocalDate;

backend/src/main/java/de/effigenix/domain/production/Ingredient.java

@@ -1,6 +1,8 @@
 package de.effigenix.domain.production;
 
+import de.effigenix.shared.common.Quantity;
 import de.effigenix.shared.common.Result;
+import de.effigenix.shared.common.UnitOfMeasure;
 
 import java.math.BigDecimal;
 

backend/src/main/java/de/effigenix/domain/production/Recipe.java

@@ -1,6 +1,8 @@
 package de.effigenix.domain.production;
 
+import de.effigenix.shared.common.Quantity;
 import de.effigenix.shared.common.Result;
+import de.effigenix.shared.common.UnitOfMeasure;
 
 import java.math.BigDecimal;
 import java.time.LocalDateTime;

backend/src/main/java/de/effigenix/domain/production/YieldPercentage.java

@@ -1,5 +1,7 @@
 package de.effigenix.domain.production;
 
+import de.effigenix.shared.common.Quantity;
+import de.effigenix.shared.common.QuantityError;
 import de.effigenix.shared.common.Result;
 
 import java.math.BigDecimal;

backend/src/main/java/de/effigenix/infrastructure/config/InventoryUseCaseConfiguration.java

@@ -1,10 +1,12 @@
 package de.effigenix.infrastructure.config;
 
 import de.effigenix.application.inventory.ActivateStorageLocation;
+import de.effigenix.application.inventory.CreateStock;
 import de.effigenix.application.inventory.CreateStorageLocation;
 import de.effigenix.application.inventory.DeactivateStorageLocation;
 import de.effigenix.application.inventory.ListStorageLocations;
 import de.effigenix.application.inventory.UpdateStorageLocation;
+import de.effigenix.domain.inventory.StockRepository;
 import de.effigenix.domain.inventory.StorageLocationRepository;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
@@ -38,4 +40,11 @@ public class InventoryUseCaseConfiguration {
     public ListStorageLocations listStorageLocations(StorageLocationRepository storageLocationRepository) {
         return new ListStorageLocations(storageLocationRepository);
     }
+
+    // ==================== Stock Use Cases ====================
+
+    @Bean
+    public CreateStock createStock(StockRepository stockRepository) {
+        return new CreateStock(stockRepository);
+    }
 }

backend/src/main/java/de/effigenix/infrastructure/inventory/persistence/entity/StockEntity.java

@@ -0,0 +1,51 @@
+package de.effigenix.infrastructure.inventory.persistence.entity;
+
+import jakarta.persistence.*;
+
+import java.math.BigDecimal;
+
+@Entity
+@Table(name = "stocks")
+public class StockEntity {
+
+    @Id
+    @Column(name = "id", nullable = false, length = 36)
+    private String id;
+
+    @Column(name = "article_id", nullable = false, length = 36)
+    private String articleId;
+
+    @Column(name = "storage_location_id", nullable = false, length = 36)
+    private String storageLocationId;
+
+    @Column(name = "minimum_level_amount", precision = 12, scale = 3)
+    private BigDecimal minimumLevelAmount;
+
+    @Column(name = "minimum_level_unit", length = 20)
+    private String minimumLevelUnit;
+
+    @Column(name = "minimum_shelf_life_days")
+    private Integer minimumShelfLifeDays;
+
+    public StockEntity() {}
+
+    // ==================== Getters & Setters ====================
+
+    public String getId() { return id; }
+    public void setId(String id) { this.id = id; }
+
+    public String getArticleId() { return articleId; }
+    public void setArticleId(String articleId) { this.articleId = articleId; }
+
+    public String getStorageLocationId() { return storageLocationId; }
+    public void setStorageLocationId(String storageLocationId) { this.storageLocationId = storageLocationId; }
+
+    public BigDecimal getMinimumLevelAmount() { return minimumLevelAmount; }
+    public void setMinimumLevelAmount(BigDecimal minimumLevelAmount) { this.minimumLevelAmount = minimumLevelAmount; }
+
+    public String getMinimumLevelUnit() { return minimumLevelUnit; }
+    public void setMinimumLevelUnit(String minimumLevelUnit) { this.minimumLevelUnit = minimumLevelUnit; }
+
+    public Integer getMinimumShelfLifeDays() { return minimumShelfLifeDays; }
+    public void setMinimumShelfLifeDays(Integer minimumShelfLifeDays) { this.minimumShelfLifeDays = minimumShelfLifeDays; }
+}

backend/src/main/java/de/effigenix/infrastructure/inventory/persistence/mapper/StockMapper.java

@@ -0,0 +1,55 @@
+package de.effigenix.infrastructure.inventory.persistence.mapper;
+
+import de.effigenix.domain.inventory.*;
+import de.effigenix.domain.masterdata.ArticleId;
+import de.effigenix.shared.common.Quantity;
+import de.effigenix.shared.common.UnitOfMeasure;
+import de.effigenix.infrastructure.inventory.persistence.entity.StockEntity;
+import org.springframework.stereotype.Component;
+
+@Component
+public class StockMapper {
+
+    public StockEntity toEntity(Stock stock) {
+        var entity = new StockEntity();
+        entity.setId(stock.id().value());
+        entity.setArticleId(stock.articleId().value());
+        entity.setStorageLocationId(stock.storageLocationId().value());
+
+        if (stock.minimumLevel() != null) {
+            entity.setMinimumLevelAmount(stock.minimumLevel().quantity().amount());
+            entity.setMinimumLevelUnit(stock.minimumLevel().quantity().uom().name());
+        }
+
+        if (stock.minimumShelfLife() != null) {
+            entity.setMinimumShelfLifeDays(stock.minimumShelfLife().days());
+        }
+
+        return entity;
+    }
+
+    public Stock toDomain(StockEntity entity) {
+        MinimumLevel minimumLevel = null;
+        if (entity.getMinimumLevelAmount() != null && entity.getMinimumLevelUnit() != null) {
+            var quantity = Quantity.reconstitute(
+                    entity.getMinimumLevelAmount(),
+                    UnitOfMeasure.valueOf(entity.getMinimumLevelUnit()),
+                    null, null
+            );
+            minimumLevel = new MinimumLevel(quantity);
+        }
+
+        MinimumShelfLife minimumShelfLife = null;
+        if (entity.getMinimumShelfLifeDays() != null) {
+            minimumShelfLife = new MinimumShelfLife(entity.getMinimumShelfLifeDays());
+        }
+
+        return Stock.reconstitute(
+                StockId.of(entity.getId()),
+                ArticleId.of(entity.getArticleId()),
+                StorageLocationId.of(entity.getStorageLocationId()),
+                minimumLevel,
+                minimumShelfLife
+        );
+    }
+}

backend/src/main/java/de/effigenix/infrastructure/inventory/persistence/repository/JpaStockRepository.java

@@ -0,0 +1,82 @@
+package de.effigenix.infrastructure.inventory.persistence.repository;
+
+import de.effigenix.domain.inventory.*;
+import de.effigenix.domain.masterdata.ArticleId;
+import de.effigenix.infrastructure.inventory.persistence.mapper.StockMapper;
+import de.effigenix.shared.common.RepositoryError;
+import de.effigenix.shared.common.Result;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.context.annotation.Profile;
+import org.springframework.dao.DataIntegrityViolationException;
+import org.springframework.stereotype.Repository;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.util.Optional;
+
+@Repository
+@Profile("!no-db")
+@Transactional(readOnly = true)
+public class JpaStockRepository implements StockRepository {
+
+    private static final Logger logger = LoggerFactory.getLogger(JpaStockRepository.class);
+
+    private final StockJpaRepository jpaRepository;
+    private final StockMapper mapper;
+
+    public JpaStockRepository(StockJpaRepository jpaRepository, StockMapper mapper) {
+        this.jpaRepository = jpaRepository;
+        this.mapper = mapper;
+    }
+
+    @Override
+    public Result<RepositoryError, Optional<Stock>> findById(StockId id) {
+        try {
+            Optional<Stock> result = jpaRepository.findById(id.value())
+                    .map(mapper::toDomain);
+            return Result.success(result);
+        } catch (Exception e) {
+            logger.trace("Database error in findById", e);
+            return Result.failure(new RepositoryError.DatabaseError(e.getMessage()));
+        }
+    }
+
+    @Override
+    public Result<RepositoryError, Optional<Stock>> findByArticleIdAndStorageLocationId(ArticleId articleId, StorageLocationId storageLocationId) {
+        try {
+            Optional<Stock> result = jpaRepository.findByArticleIdAndStorageLocationId(articleId.value(), storageLocationId.value())
+                    .map(mapper::toDomain);
+            return Result.success(result);
+        } catch (Exception e) {
+            logger.trace("Database error in findByArticleIdAndStorageLocationId", e);
+            return Result.failure(new RepositoryError.DatabaseError(e.getMessage()));
+        }
+    }
+
+    @Override
+    public Result<RepositoryError, Boolean> existsByArticleIdAndStorageLocationId(ArticleId articleId, StorageLocationId storageLocationId) {
+        try {
+            return Result.success(jpaRepository.existsByArticleIdAndStorageLocationId(articleId.value(), storageLocationId.value()));
+        } catch (Exception e) {
+            logger.trace("Database error in existsByArticleIdAndStorageLocationId", e);
+            return Result.failure(new RepositoryError.DatabaseError(e.getMessage()));
+        }
+    }
+
+    @Override
+    @Transactional
+    public Result<RepositoryError, Void> save(Stock stock) {
+        try {
+            jpaRepository.save(mapper.toEntity(stock));
+            return Result.success(null);
+        } catch (DataIntegrityViolationException e) {
+            logger.trace("Duplicate entry in save", e);
+            return Result.failure(new RepositoryError.DuplicateEntry(
+                    "Stock already exists for article " + stock.articleId().value()
+                            + " at location " + stock.storageLocationId().value()));
+        } catch (Exception e) {
+            logger.trace("Database error in save", e);
+            return Result.failure(new RepositoryError.DatabaseError(e.getMessage()));
+        }
+    }
+}

backend/src/main/java/de/effigenix/infrastructure/inventory/persistence/repository/StockJpaRepository.java

@@ -0,0 +1,13 @@
+package de.effigenix.infrastructure.inventory.persistence.repository;
+
+import de.effigenix.infrastructure.inventory.persistence.entity.StockEntity;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+import java.util.Optional;
+
+public interface StockJpaRepository extends JpaRepository<StockEntity, String> {
+
+    Optional<StockEntity> findByArticleIdAndStorageLocationId(String articleId, String storageLocationId);
+
+    boolean existsByArticleIdAndStorageLocationId(String articleId, String storageLocationId);
+}

backend/src/main/java/de/effigenix/infrastructure/inventory/web/controller/StockController.java

@@ -0,0 +1,70 @@
+package de.effigenix.infrastructure.inventory.web.controller;
+
+import de.effigenix.application.inventory.CreateStock;
+import de.effigenix.application.inventory.command.CreateStockCommand;
+import de.effigenix.domain.inventory.StockError;
+import de.effigenix.infrastructure.inventory.web.dto.CreateStockRequest;
+import de.effigenix.infrastructure.inventory.web.dto.StockResponse;
+import io.swagger.v3.oas.annotations.security.SecurityRequirement;
+import io.swagger.v3.oas.annotations.tags.Tag;
+import jakarta.validation.Valid;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.security.access.prepost.PreAuthorize;
+import org.springframework.security.core.Authentication;
+import org.springframework.web.bind.annotation.*;
+
+@RestController
+@RequestMapping("/api/inventory/stocks")
+@SecurityRequirement(name = "Bearer Authentication")
+@Tag(name = "Stocks", description = "Stock management endpoints")
+public class StockController {
+
+    private static final Logger logger = LoggerFactory.getLogger(StockController.class);
+
+    private final CreateStock createStock;
+
+    public StockController(CreateStock createStock) {
+        this.createStock = createStock;
+    }
+
+    @PostMapping
+    @PreAuthorize("hasAuthority('STOCK_WRITE')")
+    public ResponseEntity<StockResponse> createStock(
+            @Valid @RequestBody CreateStockRequest request,
+            Authentication authentication
+    ) {
+        logger.info("Creating stock for article: {} at location: {} by actor: {}",
+                request.articleId(), request.storageLocationId(), authentication.getName());
+
+        var cmd = new CreateStockCommand(
+                request.articleId(), request.storageLocationId(),
+                request.minimumLevelAmount(), request.minimumLevelUnit(),
+                request.minimumShelfLifeDays()
+        );
+        var result = createStock.execute(cmd);
+
+        if (result.isFailure()) {
+            throw new StockDomainErrorException(result.unsafeGetError());
+        }
+
+        logger.info("Stock created: {}", result.unsafeGetValue().id().value());
+        return ResponseEntity.status(HttpStatus.CREATED)
+                .body(StockResponse.from(result.unsafeGetValue()));
+    }
+
+    public static class StockDomainErrorException extends RuntimeException {
+        private final StockError error;
+
+        public StockDomainErrorException(StockError error) {
+            super(error.message());
+            this.error = error;
+        }
+
+        public StockError getError() {
+            return error;
+        }
+    }
+}

backend/src/main/java/de/effigenix/infrastructure/inventory/web/dto/CreateStockRequest.java

@@ -0,0 +1,11 @@
+package de.effigenix.infrastructure.inventory.web.dto;
+
+import jakarta.validation.constraints.NotBlank;
+
+public record CreateStockRequest(
+        @NotBlank String articleId,
+        @NotBlank String storageLocationId,
+        String minimumLevelAmount,
+        String minimumLevelUnit,
+        Integer minimumShelfLifeDays
+) {}

backend/src/main/java/de/effigenix/infrastructure/inventory/web/dto/StockResponse.java

@@ -0,0 +1,42 @@
+package de.effigenix.infrastructure.inventory.web.dto;
+
+import de.effigenix.domain.inventory.Stock;
+import io.swagger.v3.oas.annotations.media.Schema;
+
+import java.math.BigDecimal;
+
+@Schema(requiredProperties = {"id", "articleId", "storageLocationId"})
+public record StockResponse(
+        String id,
+        String articleId,
+        String storageLocationId,
+        @Schema(nullable = true) MinimumLevelResponse minimumLevel,
+        @Schema(nullable = true) Integer minimumShelfLifeDays
+) {
+
+    public static StockResponse from(Stock stock) {
+        MinimumLevelResponse minimumLevel = null;
+        if (stock.minimumLevel() != null) {
+            minimumLevel = new MinimumLevelResponse(
+                    stock.minimumLevel().quantity().amount(),
+                    stock.minimumLevel().quantity().uom().name()
+            );
+        }
+
+        Integer shelfLifeDays = null;
+        if (stock.minimumShelfLife() != null) {
+            shelfLifeDays = stock.minimumShelfLife().days();
+        }
+
+        return new StockResponse(
+                stock.id().value(),
+                stock.articleId().value(),
+                stock.storageLocationId().value(),
+                minimumLevel,
+                shelfLifeDays
+        );
+    }
+
+    @Schema(requiredProperties = {"amount", "unit"})
+    public record MinimumLevelResponse(BigDecimal amount, String unit) {}
+}

backend/src/main/java/de/effigenix/infrastructure/inventory/web/exception/InventoryErrorHttpStatusMapper.java

@@ -1,6 +1,7 @@
 package de.effigenix.infrastructure.inventory.web.exception;
 
 import de.effigenix.domain.inventory.StorageLocationError;
+import de.effigenix.domain.inventory.StockError;
 
 public final class InventoryErrorHttpStatusMapper {
 
@@ -20,4 +21,17 @@ public final class InventoryErrorHttpStatusMapper {
             case StorageLocationError.RepositoryFailure e -> 500;
         };
     }
+
+    public static int toHttpStatus(StockError error) {
+        return switch (error) {
+            case StockError.StockNotFound e -> 404;
+            case StockError.DuplicateStock e -> 409;
+            case StockError.InvalidMinimumLevel e -> 400;
+            case StockError.InvalidMinimumShelfLife e -> 400;
+            case StockError.InvalidArticleId e -> 400;
+            case StockError.InvalidStorageLocationId e -> 400;
+            case StockError.Unauthorized e -> 403;
+            case StockError.RepositoryFailure e -> 500;
+        };
+    }
 }

backend/src/main/java/de/effigenix/infrastructure/production/persistence/mapper/RecipeMapper.java

@@ -4,6 +4,8 @@ import de.effigenix.domain.production.*;
 import de.effigenix.infrastructure.production.persistence.entity.IngredientEntity;
 import de.effigenix.infrastructure.production.persistence.entity.ProductionStepEntity;
 import de.effigenix.infrastructure.production.persistence.entity.RecipeEntity;
+import de.effigenix.shared.common.Quantity;
+import de.effigenix.shared.common.UnitOfMeasure;
 import org.springframework.stereotype.Component;
 
 import java.util.List;

backend/src/main/java/de/effigenix/infrastructure/usermanagement/web/exception/GlobalExceptionHandler.java

@@ -1,6 +1,7 @@
 package de.effigenix.infrastructure.usermanagement.web.exception;
 
 import de.effigenix.domain.inventory.StorageLocationError;
+import de.effigenix.domain.inventory.StockError;
 import de.effigenix.domain.masterdata.ArticleError;
 import de.effigenix.domain.masterdata.ProductCategoryError;
 import de.effigenix.domain.masterdata.CustomerError;
@@ -8,6 +9,7 @@ import de.effigenix.domain.masterdata.SupplierError;
 import de.effigenix.domain.production.RecipeError;
 import de.effigenix.domain.usermanagement.UserError;
 import de.effigenix.infrastructure.inventory.web.controller.StorageLocationController;
+import de.effigenix.infrastructure.inventory.web.controller.StockController;
 import de.effigenix.infrastructure.inventory.web.exception.InventoryErrorHttpStatusMapper;
 import de.effigenix.infrastructure.masterdata.web.controller.ArticleController;
 import de.effigenix.infrastructure.masterdata.web.controller.CustomerController;
@@ -204,6 +206,29 @@ public class GlobalExceptionHandler {
         return ResponseEntity.status(status).body(errorResponse);
     }
 
+    @ExceptionHandler(StockController.StockDomainErrorException.class)
+    public ResponseEntity<ErrorResponse> handleStockDomainError(
+            StockController.StockDomainErrorException ex,
+            HttpServletRequest request
+    ) {
+        StockError error = ex.getError();
+        int status = InventoryErrorHttpStatusMapper.toHttpStatus(error);
+        logDomainError("Stock", error.code(), error.message(), status);
+
+        String clientMessage = status >= 500
+                ? "An internal error occurred"
+                : error.message();
+
+        ErrorResponse errorResponse = ErrorResponse.from(
+                error.code(),
+                clientMessage,
+                status,
+                request.getRequestURI()
+        );
+
+        return ResponseEntity.status(status).body(errorResponse);
+    }
+
     @ExceptionHandler(RecipeController.RecipeDomainErrorException.class)
     public ResponseEntity<ErrorResponse> handleRecipeDomainError(
             RecipeController.RecipeDomainErrorException ex,

backend/src/main/java/de/effigenix/shared/common/Quantity.java

@@ -1,13 +1,11 @@
-package de.effigenix.domain.production;
-
-import de.effigenix.shared.common.Result;
+package de.effigenix.shared.common;
 
 import java.math.BigDecimal;
 import java.math.RoundingMode;
 import java.util.Objects;
 
 /**
- * Value Object representing a production quantity with optional Catch-Weight (dual quantity).
+ * Value Object representing a quantity with optional Catch-Weight (dual quantity).
  *
  * <p>Primary quantity is always required (amount + unit of measure).
  * Secondary quantity (catch-weight) is optional and used when goods are counted

backend/src/main/java/de/effigenix/shared/common/QuantityError.java

@@ -1,4 +1,4 @@
-package de.effigenix.domain.production;
+package de.effigenix.shared.common;
 
 /**
  * Domain errors for Quantity-related Value Objects.

backend/src/main/java/de/effigenix/shared/common/RepositoryError.java

@@ -16,6 +16,9 @@ public sealed interface RepositoryError {
         }
     }
 
+    record DuplicateEntry(String message) implements RepositoryError {
+    }
+
     record DatabaseError(String message) implements RepositoryError {
     }
 }

backend/src/main/java/de/effigenix/shared/common/UnitOfMeasure.java

@@ -1,7 +1,7 @@
-package de.effigenix.domain.production;
+package de.effigenix.shared.common;
 
 /**
- * Unit of Measure for production quantities.
+ * Unit of Measure for quantities.
  * Supports mass, volume, length, and piece-based units.
  */
 public enum UnitOfMeasure {

backend/src/main/resources/application-prod.yml

@@ -6,10 +6,8 @@ springdoc:
 
 logging:
   level:
-    root: WARN
+    root: INFO
     de.effigenix: INFO
-    org.springframework.security: WARN
-    org.hibernate.SQL: WARN
 
 server:
   error:

backend/src/main/resources/application.yml

@@ -44,8 +44,6 @@ logging:
   level:
     root: INFO
     de.effigenix: DEBUG
-    org.springframework.security: DEBUG
-    org.hibernate.SQL: DEBUG
 
 # CORS Configuration
 effigenix:

backend/src/main/resources/db/changelog/changes/013-create-stock-schema.xml

@@ -0,0 +1,38 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<databaseChangeLog
+        xmlns="http://www.liquibase.org/xml/ns/dbchangelog"
+        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+        xsi:schemaLocation="http://www.liquibase.org/xml/ns/dbchangelog
+        http://www.liquibase.org/xml/ns/dbchangelog/dbchangelog-latest.xsd">
+
+    <changeSet id="012-create-stocks-table" author="effigenix">
+        <createTable tableName="stocks">
+            <column name="id" type="VARCHAR(36)">
+                <constraints primaryKey="true" nullable="false"/>
+            </column>
+            <column name="article_id" type="VARCHAR(36)">
+                <constraints nullable="false"
+                             foreignKeyName="fk_stocks_article"
+                             references="articles(id)"/>
+            </column>
+            <column name="storage_location_id" type="VARCHAR(36)">
+                <constraints nullable="false"
+                             foreignKeyName="fk_stocks_storage_location"
+                             references="storage_locations(id)"/>
+            </column>
+            <column name="minimum_level_amount" type="DECIMAL(12,3)"/>
+            <column name="minimum_level_unit" type="VARCHAR(20)"/>
+            <column name="minimum_shelf_life_days" type="INTEGER"/>
+        </createTable>
+        <addUniqueConstraint tableName="stocks"
+                             columnNames="article_id, storage_location_id"
+                             constraintName="uq_stocks_article_location"/>
+        <createIndex tableName="stocks" indexName="idx_stocks_article_id">
+            <column name="article_id"/>
+        </createIndex>
+        <createIndex tableName="stocks" indexName="idx_stocks_storage_location_id">
+            <column name="storage_location_id"/>
+        </createIndex>
+    </changeSet>
+
+</databaseChangeLog>

backend/src/main/resources/db/changelog/db.changelog-master.xml

@@ -17,5 +17,6 @@
     <include file="db/changelog/changes/010-create-recipe-schema.xml"/>
     <include file="db/changelog/changes/011-create-recipe-ingredients-table.xml"/>
     <include file="db/changelog/changes/012-create-recipe-production-steps-table.xml"/>
+    <include file="db/changelog/changes/013-create-stock-schema.xml"/>
 
 </databaseChangeLog>