Fail to delete I-Note

When deleting an I-Note, the frontend dispatches epub/deleteEPub with a string payload, but the thunk expects an object shape ({ ePubId }).
The deletion fails.

Steps to Reproduce
1. Open an I-Note
2. Click Delete and confirm.
3. FrontEnd shows failure to delete (Observe request returns 404 in the Network Tab)

Trace the delete action from the I-Note frontend through epub/deleteEPub and compare the dispatched string payload with the thunk's expected { ePubId } object. Reproduce the deletion in the Network tab; done means the request no longer returns 404 and the I-Note is deleted successfully.

Written by the indexing model from the issue text.