fix(app): improve light mode theming

- Make PaseoLogo theme-aware (uses foreground color instead of hardcoded white)
- Add shadow tokens (sm/md/lg) to theme with per-scheme opacity, radius, and offset
- Replace all 16 hardcoded shadow instances with spreadable theme.shadow tokens
- Fix button icon color for default variant (use accentForeground, not foreground)
- Fix dark background flash on startup (root layout used hardcoded darkTheme)
- Add theme.colorScheme to replace fragile hex-string dark mode detection
- Add scrollbarHandle and surfaceWorkspace tokens to eliminate isDark branching

packages/app/src/screens/workspace/workspace-screen.tsx

@@ -8,7 +8,6 @@ import {
   Platform,
   Pressable,
   Text,
-  useColorScheme,
   View,
 } from "react-native";
 import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
@@ -578,8 +577,7 @@ function useCloseTabs(): UseCloseTabsResult {
 function WorkspaceScreenContent({ serverId, workspaceId }: WorkspaceScreenProps) {
   const { theme } = useUnistyles();
   const insets = useSafeAreaInsets();
-  const isDarkMode = useColorScheme() === "dark";
-  const mainBackgroundColor = isDarkMode ? theme.colors.surface1 : theme.colors.surface0;
+  const mainBackgroundColor = theme.colors.surfaceWorkspace;
   const toast = useToast();
   const isMobile = isCompactFormFactor();
   const isFocusModeEnabled = usePanelStore((state) => state.desktop.focusModeEnabled);