Fix 500 error when field mapping has null field or no search results

- Skip field mappings with null/empty field values in convertFieldMappingsToDto
- Return empty DTO instead of throwing when no search results found
- Remove unnecessary try/catch workaround in researchPart

src/Controller/BulkInfoProviderImportController.php

@@ -68,6 +68,10 @@ class BulkInfoProviderImportController extends AbstractController
     {
         $dtos = [];
         foreach ($fieldMappings as $mapping) {
+            // Skip entries where field is null/empty (e.g. user added a row but didn't select a field)
+            if (empty($mapping['field'])) {
+                continue;
+            }
             $dtos[] = new BulkSearchFieldMappingDTO(field: $mapping['field'], providers: $mapping['providers'], priority: $mapping['priority'] ?? 1);
         }
         return $dtos;
@@ -472,16 +476,7 @@ class BulkInfoProviderImportController extends AbstractController
             $fieldMappingDtos = $job->getFieldMappings();
             $prefetchDetails = $job->isPrefetchDetails();
 
-            try {
-                $searchResultsDto = $this->bulkService->performBulkSearch([$part], $fieldMappingDtos, $prefetchDetails);
-            } catch (\Exception $searchException) {
-                // Handle "no search results found" as a normal case, not an error
-                if (str_contains($searchException->getMessage(), 'No search results found')) {
-                    $searchResultsDto = null;
-                } else {
-                    throw $searchException;
-                }
-            }
+            $searchResultsDto = $this->bulkService->performBulkSearch([$part], $fieldMappingDtos, $prefetchDetails);
 
             // Update the job's search results for this specific part efficiently
             $this->updatePartSearchResults($job, $searchResultsDto[0] ?? null);

src/Services/InfoProviderSystem/BulkInfoProviderService.php

@@ -46,7 +46,6 @@ final class BulkInfoProviderService
         }
 
         $partResults = [];
-        $hasAnyResults = false;
 
         // Group providers by batch capability
         $batchProviders = [];
@@ -88,7 +87,6 @@ final class BulkInfoProviderService
             );
 
             if (!empty($allResults)) {
-                $hasAnyResults = true;
                 $searchResults = $this->formatSearchResults($allResults);
             }
 
@@ -99,10 +97,6 @@ final class BulkInfoProviderService
             );
         }
 
-        if (!$hasAnyResults) {
-            throw new \RuntimeException('No search results found for any of the selected parts');
-        }
-
         $response = new BulkSearchResponseDTO($partResults);
 
         // Prefetch details if requested