Add file uploads for photos and family icons

flutter_app/lib/services/family_service.dart

@@ -1,3 +1,5 @@
+import "dart:typed_data";
+
 import "../config/api_config.dart";
 import "../models/family_member.dart";
 import "api_client.dart";
@@ -23,6 +25,7 @@ class FamilyService {
       final created = FamilyMember(
         id: "family-${DateTime.now().millisecondsSinceEpoch}",
         name: member.name,
+        iconUrl: member.iconUrl,
         emoji: member.emoji,
         color: member.color,
         order: member.order,
@@ -51,6 +54,22 @@ class FamilyService {
     return FamilyMember.fromJson(data);
   }
 
+  Future<String> uploadFamilyIcon({
+    required Uint8List bytes,
+    required String filename,
+  }) async {
+    if (ApiConfig.useMockData) {
+      return "mock://$filename";
+    }
+    final data = await _client.postMultipart(
+      "${ApiConfig.family}/upload-icon",
+      fieldName: "file",
+      bytes: bytes,
+      filename: filename,
+    );
+    return data["url"] as String? ?? "";
+  }
+
   Future<void> deleteFamilyMember(String id) async {
     if (ApiConfig.useMockData) {
       MockDataStore.familyMembers.removeWhere((item) => item.id == id);