Redesign AdminSettings with tabs navigation and favorites

- Add tab-based navigation (Favorites, Branding, Theme, Payments, etc.)
- Create useFavoriteSettings hook for localStorage-based favorites
- Create SettingCard component for consistent setting display
- Add global search functionality
- Implement collapsible sections for theme presets and colors
- Group settings by meta-categories (payments, subscriptions, etc.)
- Add dropdown for additional categories (More menu)
- Modern UI with improved spacing and interactions

src/hooks/useFavoriteSettings.ts

@@ -0,0 +1,49 @@
+import { useState, useEffect, useCallback } from 'react'
+
+const STORAGE_KEY = 'admin_favorite_settings'
+
+export function useFavoriteSettings() {
+  const [favorites, setFavorites] = useState<string[]>(() => {
+    try {
+      const stored = localStorage.getItem(STORAGE_KEY)
+      return stored ? JSON.parse(stored) : []
+    } catch {
+      return []
+    }
+  })
+
+  // Sync to localStorage
+  useEffect(() => {
+    try {
+      localStorage.setItem(STORAGE_KEY, JSON.stringify(favorites))
+    } catch {
+      // Ignore storage errors
+    }
+  }, [favorites])
+
+  const toggleFavorite = useCallback((settingKey: string) => {
+    setFavorites(prev => {
+      if (prev.includes(settingKey)) {
+        return prev.filter(key => key !== settingKey)
+      } else {
+        return [...prev, settingKey]
+      }
+    })
+  }, [])
+
+  const isFavorite = useCallback((settingKey: string) => {
+    return favorites.includes(settingKey)
+  }, [favorites])
+
+  const clearFavorites = useCallback(() => {
+    setFavorites([])
+  }, [])
+
+  return {
+    favorites,
+    toggleFavorite,
+    isFavorite,
+    clearFavorites,
+    count: favorites.length
+  }
+}