.app-shell min-height is now 100vh with a 100dvh override (the 3.3rem was a
donor-app top-bar leftover; ThemeShell has no top bar) and the lg+ sticky
rail is 100vh/100dvh. Source bumped to 0.5.3, UNPUBLISHED. Adds a static
regression test and fixes the CS8602 in NavStateScriptTests (0 warnings).
Browser-checked via Overview on local 0.5.2 vs 0.5.3 packages: at 390x844 a
short page went from a 791px shell (53px gap) to 844px, no extra scroll;
1440x900 rail stays sticky full-height.
Claude-Session: https://claude.ai/code/session_01GT67AEHd2Acv1YPwGfXEoV