feat: add MyWhoosh token persistence

app/mywhoosh/models.py

@@ -0,0 +1,17 @@
+from dataclasses import dataclass
+from datetime import datetime
+
+
+@dataclass(frozen=True)
+class MyWhooshToken:
+    access_token: str
+    refresh_token: str | None
+    whoosh_id: str | None
+
+
+@dataclass(frozen=True)
+class MyWhooshActivity:
+    id: str
+    title: str
+    activity_file_id: str
+    started_at: datetime | None