feat(ui): 重构核心 UI 组件库，新增 shadcn/ui 组件

- 重构 Button、Card、Badge、Input、Textarea 等基础组件
- 新增 Accordion、Alert、Dialog、Dropdown、Form 等 shadcn/ui 组件
- 新增 AnimatedCounter、StatsShowcase、MetricCard 等数据展示组件
- 新增 ScrollReveal 滚动动画组件
- 重构 Toast 通知系统与 Tooltip 提示组件
- 更新设计令牌系统，对齐新品牌视觉

src/components/ui/index.ts

@@ -0,0 +1,204 @@
+// === shadcn/ui 标准组件 ===
+export { Button, buttonVariants } from './button';
+export type { ButtonProps } from './button';
+
+export {
+  Card,
+  CardHeader,
+  CardFooter,
+  CardTitle,
+  CardAction,
+  CardDescription,
+  CardContent,
+} from './card';
+
+export { Badge, badgeVariants } from './badge';
+
+export { Input } from './input';
+
+export { Textarea } from './textarea';
+
+export { Label, labelVariants } from './label';
+
+export { LabeledInput } from './labeled-input';
+export type { LabeledInputProps } from './labeled-input';
+
+export { LabeledTextarea } from './labeled-textarea';
+export type { LabeledTextareaProps } from './labeled-textarea';
+
+export { Skeleton, SkeletonText, SkeletonCard, SkeletonList, SkeletonHero, SkeletonForm } from './skeleton';
+
+// === 表单类 ===
+export { Checkbox } from './checkbox';
+export { Switch } from './switch';
+export { RadioGroup, RadioGroupItem } from './radio-group';
+export { Slider } from './slider';
+export {
+  Select,
+  SelectGroup,
+  SelectValue,
+  SelectTrigger,
+  SelectContent,
+  SelectLabel,
+  SelectItem,
+  SelectSeparator,
+  SelectScrollUpButton,
+  SelectScrollDownButton,
+} from './select';
+export {
+  Form,
+  FormField,
+  FormItem,
+  FormLabel,
+  FormControl,
+  FormDescription,
+  FormMessage,
+  useFormField,
+  useFormWithZod,
+} from './form';
+
+// === 反馈类 ===
+export { Alert, AlertTitle, AlertDescription, alertVariants } from './alert';
+export {
+  AlertDialog,
+  AlertDialogPortal,
+  AlertDialogOverlay,
+  AlertDialogTrigger,
+  AlertDialogContent,
+  AlertDialogHeader,
+  AlertDialogFooter,
+  AlertDialogTitle,
+  AlertDialogDescription,
+  AlertDialogAction,
+  AlertDialogCancel,
+} from './alert-dialog';
+export {
+  Dialog,
+  DialogPortal,
+  DialogOverlay,
+  DialogTrigger,
+  DialogClose,
+  DialogContent,
+  DialogHeader,
+  DialogFooter,
+  DialogTitle,
+  DialogDescription,
+} from './dialog';
+export { Progress } from './progress';
+
+// === 导航类 ===
+export {
+  DropdownMenu,
+  DropdownMenuTrigger,
+  DropdownMenuContent,
+  DropdownMenuItem,
+  DropdownMenuCheckboxItem,
+  DropdownMenuRadioItem,
+  DropdownMenuLabel,
+  DropdownMenuSeparator,
+  DropdownMenuShortcut,
+  DropdownMenuGroup,
+  DropdownMenuPortal,
+  DropdownMenuSub,
+  DropdownMenuSubContent,
+  DropdownMenuSubTrigger,
+  DropdownMenuRadioGroup,
+} from './dropdown-menu';
+export { Tabs, TabsList, TabsTrigger, TabsContent } from './tabs';
+export { Accordion, AccordionItem, AccordionTrigger, AccordionContent } from './accordion';
+export {
+  Pagination,
+  PaginationContent,
+  PaginationLink,
+  PaginationItem,
+  PaginationPrevious,
+  PaginationNext,
+  PaginationEllipsis,
+} from './pagination';
+export {
+  Breadcrumb,
+  BreadcrumbList,
+  BreadcrumbItem,
+  BreadcrumbLink,
+  BreadcrumbPage,
+  BreadcrumbSeparator,
+  BreadcrumbEllipsis,
+} from './breadcrumb';
+
+// === 数据类 ===
+export {
+  Table,
+  TableHeader,
+  TableBody,
+  TableFooter,
+  TableHead,
+  TableRow,
+  TableCell,
+  TableCaption,
+} from './table';
+export { Avatar, AvatarImage, AvatarFallback } from './avatar';
+export { Separator } from './separator';
+export { ScrollArea, ScrollBar } from './scroll-area';
+
+// === 浮层类 ===
+export {
+  Tooltip,
+  TooltipTrigger,
+  TooltipContent,
+  TooltipProvider,
+  LegacyTooltip,
+} from './tooltip';
+export { Popover, PopoverTrigger, PopoverContent, PopoverAnchor } from './popover';
+export { HoverCard, HoverCardTrigger, HoverCardContent } from './hover-card';
+export {
+  ContextMenu,
+  ContextMenuTrigger,
+  ContextMenuContent,
+  ContextMenuItem,
+  ContextMenuCheckboxItem,
+  ContextMenuRadioItem,
+  ContextMenuLabel,
+  ContextMenuSeparator,
+  ContextMenuShortcut,
+  ContextMenuGroup,
+  ContextMenuPortal,
+  ContextMenuSub,
+  ContextMenuSubContent,
+  ContextMenuSubTrigger,
+  ContextMenuRadioGroup,
+} from './context-menu';
+
+// === Toast (Sonner) ===
+export { Toaster, toast } from './sonner';
+export { Toast } from './toast';
+
+// === 业务自定义组件（保留） ===
+export { ScrollReveal, StaggerReveal } from './scroll-reveal';
+export { ScrollProgress } from './scroll-progress';
+export { BackToTop } from './back-to-top';
+export { StaticLink } from './static-link';
+export { Spinner, LoadingState, PageLoader, useLoadingState } from './loading-state';
+export { ErrorBoundary } from './error-boundary';
+export { PageTransition, StaggerChildren } from './page-transition';
+export {
+  EASE_OUT,
+  GrainOverlay,
+  FloatingInkParticles,
+  SectionLabel,
+} from './page-decoration';
+export {
+  GeometricDecoration,
+  DataBar,
+  GradientDivider,
+  BrandStamp,
+} from './brand-visuals';
+export { InkGlowCard } from './ink-glow-card';
+export { ChallengeCard } from './challenge-card';
+export { ProductCard as UiProductCard } from './product-card';
+export { DetailSwipeNav } from './detail-swipe-nav';
+export { HeroInkBackground } from './hero-ink-background';
+export { FlipClock } from './flip-clock';
+export { AnimatedCounter } from './animated-counter';
+export { MetricCard } from './metric-card';
+export { StatsShowcase } from './stats-showcase';
+export { MilestoneTimeline } from './milestone-timeline';