Finally, I got it working via the WLJS Notebook.app, and with little thanks to the inadequate documentation and with some flaky behavior of the app.
First little snag: when I tried to open it, I got the not-unexpected error that app is damaged and could not be opened. executing "xattr -c /Applications/WLJS\ Notebook.app " fixed that.
Next, I opened WLJS Notebook app. Eventually it asked question, "Do you hae Wolfram Engine installed", and I accpted default asnwer "yes". Next I got a reply that was nearly unreadable, owing to black text on a DARK blue background - a really dumb design choice! I think it says, "Please locate an executable called wolframscript or WolframKernel."
Well that's a big enigmatic, as there are two places where I find a "wolframscript", including:
/Applications/WolframScript.app
/Applications/WolframScript.app/Contents/MacOS/wolframscript
I tried selecting the first of these -- the app, not the executable. Nothing happened after I clicked Open in the Finder window the app had opened, so I next navigated in the same Finder window to teh wolframscript executable and pressed Enter. That seemed to satisfy the app.
After lots of output in the app window, similar to what I had seen when trying to install from the Terminal, eventually I did get a window with a left-side panel seeming to be a table of contents, "../, 01-Introduction, 02 - Dhnamics", etc.
Next, clicking, say "01- Introduction" momentarily opens a list of items below that, but the almost immediately disappears, making it impossible to select any item from it.
After a while, clicking one of those main-level items did keep the sublist displayed, and I was able to finally to open, e.g., Plot3D.win and to evaluate the input cells there.
When I close the app and open it again, there's a delay as a whole bunch of output is written to one pop-up window, ending with this;
In[2]:=
Hee uvTask: 2
Connected
asyncsocket id: c71441fc-e366-4af5-a1ee-77bbedc8e890
Started
---print---
>> "Created server with sid: 0"
BinaryWrite::stream:
Missing[KeyAbsent, Null][channel]
is not a string, SocketObject, InputStream[ ], or OutputStream[ ].
Warning
BinaryWrite::stream:
Missing[KeyAbsent, Null][channel]
is not a string, SocketObject, InputStream[ ], or OutputStream[ ].
Warning
BinaryWrite::stream:
Missing[KeyAbsent, Null][channel]
is not a string, SocketObject, InputStream[ ], or OutputStream[ ].
General::stop: Further output of BinaryWrite::stream
will be suppressed during this calculation.
Warning
---print---
>> "LPM >> project directory >> /Users/murray/Library/Application \
Support/wljs-frontend/Packages/wljs-wlx-support"
---print---
>> "LPM >> fetching paclet infos..."
---print---
>> "LPM >> PASSIVE MODE"
Global`NotebookEventFire::shdw:
Symbol NotebookEventFire appears in multiple contexts
{Global`, JerryI`WolframJSFrontend`Notebook`}; definitions in context
Global` may shadow or be shadowed by other definitions.
Only after that does the main window of the app open and I can proceed.
I presume I'm dealing here with a server-client interchange, but the appearance is somewhat clumsy.
