Sync markToUpdate and shouldCreateBoard in syncMeta

[magush27]

CREATE_API_BOARD_SUCCESS now stamps syncMeta as PENDING for every board that received markToUpdate: true or shouldCreateBoard: true, so the standard syncBoards() cycle can recover them even if updateApiMarkedBoards fails.

How to test:

1. Open the app and go to any board
2. Open Redux DevTools, go to the State tab
3. Unlock the board and create a new folder tile (this creates a local child board with a short ID)
4. Wait a few seconds for the sync to run
5. In Redux DevTools, find the CREATE_API_BOARD_SUCCESS action
6. In the state diff, check syncMeta — the parent board's entry should show { status: 'pending' }
7. Find the UPDATE_API_BOARD_SUCCESS action that fires shortly after
8. Check that the parent board is now { status: 'synced' } in syncMeta
9. Check that the parent board's tile loadBoard field now contains a long MongoDB ObjectId (not the original short local ID)

Expected: the parent board goes pending → synced and its tile points to the server ID.

Closes #2198