react/ts custom widget fails to render with "Failed to load model class" exception

[zkbitcoin]

Reproduce

1. create simple project using steps (leave defaults, project name will be myproject)

https://ipywidgets.readthedocs.io/en/latest/examples/Widget%20Custom.html

2. serve ipynb (via react code) file containing (myproject.ipynb)

import myproject
w = myproject.ExampleWidget()

typescript client uses

import {CellSidebarRun, Jupyter, Notebook} from '@datalayer/jupyter-react';

Notebook
readOnly={true}
path="/myproject.ipynb"
CellSidebar={CellSidebarRun}

3. js error will occur:

[Open Browser Console for more detailed log - Double click to close this message]
Failed to load model class 'ExampleModel' from module 'myproject'
Error: Script error for "myproject"
https://requirejs.org/docs/errors.html#scripterror
at makeError (https://cdnjs.cloudflare.com/ajax/libs/require.js/2.3.6/require.min.js:1:1795)
at HTMLScriptElement.onScriptError (https://cdnjs.cloudflare.com/ajax/libs/require.js/2.3.6/require.min.js:1:17084)

console shows an attempt to load form registry potentially pointing to issue with registration

Loading from https://cdn.jsdelivr.net/npm/ for myproject@^0.1.0

Expected behavior

invoking same widget via running jupyter notebook works just fine, only react/ts code interface fails

Context

latest jupiter-ui npm libraries, mac, chrome

myproject % jupyter --version
Selected Jupyter core packages...
IPython : 8.26.0
ipykernel : 6.29.5
ipywidgets : 8.1.3
jupyter_client : 8.6.2
jupyter_core : 5.7.2
jupyter_server : 2.14.1
jupyterlab : 4.2.3
nbclient : 0.10.0
nbconvert : 7.16.4
nbformat : 5.10.4
notebook : 7.2.1
qtconsole : not installed
traitlets : 5.14.3

Note steps below wont work with latest jupyter version also ipywidgets work just fine with jupyter-ui (react/ts framework)

jupyter nbextension install --sys-prefix --symlink --overwrite --py myproject
jupyter nbextension enable --sys-prefix --py myproject