Show a bad save name when the plugin opens, and remove unused SCAPE sheet width code

[bls337]

• A bad save name is now shown when the plugin opens, in the error color with the reason in its tooltip. The field's check was attached after the field was filled, so the name looked fine until it was edited. The run still refused it.
• SCAPE runs no longer compute a sheet width they never send. SCAPE uses the galvo's X axis for the static offset, as 1.4 did. Computing the width read the camera ROI and could show "could not get camera roi". Nothing sent to the hardware changes.
• saveNamePrefix and cameraMode on the settings builder now document the IllegalArgumentException they can throw.
• Unused debug helpers are removed from the playlist table data.