Add version files and update imports for trip model; enhance error handling

lib/services/brr_export_service.dart

@@ -1,5 +1,6 @@
 import "dart:typed_data";
-import "../models/trip.dart";
+import "package:flutter/foundation.dart";
+import "../models/operations/trip.dart";
 import "../models/brr_metadata.dart";
 import "../exporters/brr_exporter.dart";
 import "../exporters/arriva_brr_exporter.dart";
@@ -37,8 +38,10 @@ class BRRExportService {
     try {
       final bytes = await _exporter.export(trips, metadata);
       return ExportResult.success(bytes);
-    } catch (e) {
+    } catch (e, stackTrace) {
+      debugPrint("[BRRExportService] exportBRR failed: $e");
+      debugPrintStack(stackTrace: stackTrace);
       return ExportResult.error(["Export failed: $e"]);
     }
   }
-}
+}

lib/services/storage_service.dart

@@ -1,4 +1,5 @@
 import "dart:convert";
+import "package:flutter/foundation.dart";
 import "package:hive_flutter/hive_flutter.dart";
 import "../models/brr_state.dart";
 
@@ -21,7 +22,9 @@ class StorageService {
 
     try {
       return BRRState.fromJson(jsonDecode(jsonString) as Map<String, dynamic>);
-    } catch (e) {
+    } catch (e, stackTrace) {
+      debugPrint("[StorageService] loadState failed: $e");
+      debugPrintStack(stackTrace: stackTrace);
       return null;
     }
   }