Add file uploads for photos and family icons

flutter_app/lib/services/photo_service.dart

@@ -1,3 +1,5 @@
+import "dart:typed_data";
+
 import "../config/api_config.dart";
 import "../models/photo.dart";
 import "api_client.dart";
@@ -38,6 +40,35 @@ class PhotoService {
     return Photo.fromJson(data);
   }
 
+  Future<Photo> uploadPhotoBytes({
+    required Uint8List bytes,
+    required String filename,
+    String caption = "",
+    bool active = true,
+  }) async {
+    if (ApiConfig.useMockData) {
+      final created = Photo(
+        id: "photo-${DateTime.now().millisecondsSinceEpoch}",
+        url: "mock://$filename",
+        caption: caption,
+        active: active,
+      );
+      MockDataStore.photos.add(created);
+      return created;
+    }
+    final data = await _client.postMultipart(
+      "${ApiConfig.photos}/upload",
+      fieldName: "file",
+      bytes: bytes,
+      filename: filename,
+      fields: {
+        "caption": caption,
+        "active": active.toString(),
+      },
+    );
+    return Photo.fromJson(data);
+  }
+
   Future<void> deletePhoto(String id) async {
     if (ApiConfig.useMockData) {
       MockDataStore.photos.removeWhere((item) => item.id == id);