feat: add firearm name lookup for webhook YAML parsing

When firearmId is absent from the YAML block, resolveFirearmId falls back
to firearmName lookup via FirearmRepository.findByName(). If both are
present, firearmId takes precedence.

src/main/java/com/onixbyte/deltaforceguide/manager/ModificationManager.java

@@ -71,6 +71,21 @@ public class ModificationManager {
                 .toList();
     }
 
+    public Long resolveFirearmId(Long firearmId, String firearmName) {
+        if (firearmId != null) {
+            return firearmId;
+        }
+        if (firearmName == null || firearmName.isBlank()) {
+            return null;
+        }
+        var matches = firearmRepository.findByName(firearmName);
+        if (matches.isEmpty()) {
+            throw new ResponseStatusException(HttpStatus.NOT_FOUND,
+                    "Firearm not found by name: " + firearmName);
+        }
+        return matches.getFirst().getId();
+    }
+
     private Modification toEntity(ModificationRequest request, Firearm firearm) {
         return Modification.builder()
                 .firearm(firearm)

src/main/java/com/onixbyte/deltaforceguide/repository/FirearmRepository.java

@@ -7,9 +7,13 @@ import org.springframework.data.domain.Pageable;
 import org.springframework.data.jpa.repository.JpaRepository;
 import org.springframework.stereotype.Repository;
 
+import java.util.List;
+
 @Repository
 public interface FirearmRepository extends JpaRepository<Firearm, Long> {
 
 	Page<Firearm> findAllByType(FirearmType type, Pageable pageable);
+
+	List<Firearm> findByName(String name);
 }
 

src/main/java/com/onixbyte/deltaforceguide/service/WebhookService.java

@@ -109,7 +109,9 @@ public class WebhookService {
     }
 
     private ModificationRequest mapToRequest(Map<String, Object> data) {
-        Long firearmId = toLong(data.get("firearmId"));
+        Long firearmId = modificationManager.resolveFirearmId(
+                toLong(data.get("firearmId")),
+                (String) data.get("firearmName"));
         String name = (String) data.get("name");
         String code = (String) data.get("code");
         List<String> tags = toStringList(data.get("tags"));