feat(ui): touch-size controls, scrollable dialogs, motion levels everywhere, load states

- Inputs and selects are 44 px on phones (36 px from sm up); default and
  small buttons get 40/36 px on phones.
- Dialogs scroll inside the viewport, so long edit forms keep their
  save button reachable on a phone.
- Dialog zoom, sheet slide, sidebar icon scale and stat-bar growth only
  move at the motion level "Voll" (motion-full), not at "Dezent".
- QueryState / ErrorState / LoadingState: loading, error with "Erneut
  versuchen", empty, data - a failed load can no longer look like an
  empty list. EmptyState takes an action for the obvious next step.

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

ApiCore-Frontend/src/components/ui/dialog.tsx

@@ -53,7 +53,7 @@ function DialogContent({
       <DialogPrimitive.Popup
         data-slot="dialog-content"
         className={cn(
-          "fixed top-1/2 left-1/2 z-50 grid w-full max-w-[calc(100%-2rem)] -translate-x-1/2 -translate-y-1/2 gap-4 rounded-2xl bg-popover p-5 text-sm text-popover-foreground shadow-[var(--shadow-elevated)] ring-1 ring-foreground/10 duration-100 outline-none sm:max-w-sm data-open:animate-in data-open:fade-in-0 data-open:zoom-in-95 data-closed:animate-out data-closed:fade-out-0 data-closed:zoom-out-95",
+          "fixed top-1/2 left-1/2 z-50 grid w-full max-w-[calc(100%-2rem)] -translate-x-1/2 -translate-y-1/2 gap-4 rounded-2xl bg-popover p-5 text-sm text-popover-foreground shadow-[var(--shadow-elevated)] ring-1 ring-foreground/10 max-h-[calc(100dvh-2rem)] overflow-y-auto overscroll-contain duration-100 outline-none sm:max-w-sm data-open:animate-in data-open:fade-in-0 motion-full:data-open:zoom-in-95 data-closed:animate-out data-closed:fade-out-0 motion-full:data-closed:zoom-out-95",
           className
         )}
         {...props}