I've developed Adobe Custom Panels for Photoshop, Illustrator, InDesign, Premiere, After Effects, and Audition. All except Photoshop debug just fine using the inspector accessed at the URL chrome://inspect/#devices in Chrome browser. (Thanks to @funkelodeon for the clue on this forum post)
As best as I can tell everything is set up correctly -- the port in the .dbug file in the panel code, as well as the "discovery network targets" list in chrome://inspect/#devices.
Any other trouble-shooting tips?