fix: request offline access on OAuth login so Google returns a refresh token

backend/app/auth.py

@@ -22,18 +22,21 @@ oauth.register(
     client_id=settings.google_client_id,
     client_secret=settings.google_client_secret,
     server_metadata_url="https://accounts.google.com/.well-known/openid-configuration",
-    client_kwargs={
+    client_kwargs={"scope": SCOPES},
-        "scope": SCOPES,
-        # access_type=offline + prompt=consent ensures we receive a refresh_token.
-        "access_type": "offline",
-        "prompt": "consent",
-    },
 )
 
 
 @router.get("/login")
 async def login(request: Request):
-    return await oauth.google.authorize_redirect(request, settings.oauth_redirect_url)
+    # access_type=offline + prompt=consent must be on the authorization URL so Google
+    # returns a refresh_token (required for background sync).
+    return await oauth.google.authorize_redirect(
+        request,
+        settings.oauth_redirect_url,
+        access_type="offline",
+        prompt="consent",
+        include_granted_scopes="true",
+    )
 
 
 @router.get("/callback")