At auto-login the Startup shortcut fired before the network was up, so Edge
--kiosk navigated to nothing and sat on a blank white page with no retry.
Point the shortcut at a hidden VBS launcher (wscript, no console flash) that
polls the kiosk URL until it responds (up to ~3 min) and only then launches
Edge fullscreen, so the first paint is the real page. Falls through to launch
anyway after the timeout so a display is never left dark.
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