The CSS-Layout was broken: `html, body, #app` had
`height: 100%; overflow: hidden` but NO `display: flex`.
The shell has `flex: 1` which only works when the parent is
a flex container, so the shell collapsed to its content
height and `.main { overflow: auto }` had no scroll
target. The user reported 'kann nicht scrollen nix anklicken
etc.' even after the previous click-bug fixes — clicks
were registered but the visible area was just the natural
content height of the shell, so there was nothing to scroll
and a large area of the viewport was blank.
Fix: make html/body a flex column (`display: flex;
flex-direction: column; height: 100%`) so the shell's
`flex: 1` actually takes the full viewport, and let
the inner shell's grid + main's overflow:auto work as
designed. Also added `#app` as a flex child for the
case where body height comes from the tauri webview's
document element instead of the html element.
This is a structural CSS fix — no Svelte or component
changes. The dev-server / Vite / NavRail issues from
previous commits are independent and remain fixed.
tomdebone
2558113235