Replaced FTDI driver; two filenames within the driver were somehow modified to include their type as an extension. Don't know what caused this, but it caused the driver to fail to run when a USB device was connected to the Mac.
Created and added the BlocklyPropClient.icns file (multi-resolution icon for the app).
Recreated the BlocklyPropClient.macos.spec file (it was somehow malformed, causing the build to generate a non-standard application bundle format; mostly flat, no Contents/MacOS... hierarchy).
Updated package and sign script to properly verify code signature in the new bundle format.
Added application version to the macos.spec to inject into the bundle's Info.plist file.
Updated build instructions to include .macos.spec file details.