fix: fix typos

Author: nozomuikuta

src/data/timetable.json

@@ -4003,7 +4003,7 @@
           },
           {
             "id": "75d427fb-af6a-4a26-8cca-4d5a95e98f71",
-            "title": "platinum sponser",
+            "title": "platinum sponsor",
             "description": null,
             "startsAt": "2025-09-28T18:00:00",
             "endsAt": "2025-09-28T18:20:00",
@@ -6297,7 +6297,7 @@
             "name": "Room 1",
             "session": {
               "id": "75d427fb-af6a-4a26-8cca-4d5a95e98f71",
-              "title": "platinum sponser",
+              "title": "platinum sponsor",
               "description": null,
               "startsAt": "2025-09-28T18:00:00",
               "endsAt": "2025-09-28T18:20:00",