fix(ui): use full viewport height for layout containers

- Update App.tsx to set `h-[calc(100vh)]` instead of
  `h-[calc(100vh-2rem)]`

- Update Sidebar component to set `min-h-[calc(100vh)]` instead of
  `min-h-[calc(100vh-2rem)]`

- Ensures consistent full-height layout across platforms

Author: bl-ue

frontend/src/App.tsx

@@ -315,9 +315,7 @@ function RootLayout() {
         <div
           className={cn(
             "w-full",
-            __WEB__ || platform() !== "windows"
-              ? "h-full"
-              : "h-[calc(100vh-2rem)]"
+            __WEB__ || platform() !== "windows" ? "h-full" : "h-[calc(100vh)]"
           )}
         >
           <RootLayoutContent />

frontend/src/components/ui/sidebar.tsx

@@ -174,7 +174,7 @@ function SidebarProvider({
             "group/sidebar-wrapper has-data-[variant=inset]:bg-sidebar flex w-full",
             __WEB__ || platform() !== "windows"
               ? "min-h-full"
-              : "min-h-[calc(100vh-2rem)]",
+              : "min-h-[calc(100vh)]",
             className
           )}
           {...props}