feat(client): UI primitives 基线（E2）

- 引入 Radix Dialog/DropdownMenu/Tabs + CVA
- 新增 Button/Input/Dialog/Tabs/Table/Card 等组件（本地拷贝单向同步）
- 增加 touch-target(44px) 样式基础

client/src/components/ui/dialog.tsx

@@ -0,0 +1,76 @@
+import * as React from "react";
+import * as DialogPrimitive from "@radix-ui/react-dialog";
+import { cn } from "../../lib/utils";
+
+export const Dialog = DialogPrimitive.Root;
+export const DialogTrigger = DialogPrimitive.Trigger;
+export const DialogClose = DialogPrimitive.Close;
+
+export const DialogPortal = DialogPrimitive.Portal;
+
+export const DialogOverlay = React.forwardRef<
+  React.ElementRef<typeof DialogPrimitive.Overlay>,
+  React.ComponentPropsWithoutRef<typeof DialogPrimitive.Overlay>
+>(({ className, ...props }, ref) => (
+  <DialogPrimitive.Overlay
+    ref={ref}
+    className={cn("fixed inset-0 z-50 bg-black/40 backdrop-blur-sm", className)}
+    {...props}
+  />
+));
+
+DialogOverlay.displayName = "DialogOverlay";
+
+export const DialogContent = React.forwardRef<
+  React.ElementRef<typeof DialogPrimitive.Content>,
+  React.ComponentPropsWithoutRef<typeof DialogPrimitive.Content>
+>(({ className, ...props }, ref) => (
+  <DialogPortal>
+    <DialogOverlay />
+    <DialogPrimitive.Content
+      ref={ref}
+      className={cn(
+        "fixed left-1/2 top-1/2 z-50 w-[92vw] max-w-lg -translate-x-1/2 -translate-y-1/2 rounded-xl border border-slate-200 bg-white p-6 shadow-lg focus-visible:outline-none",
+        className,
+      )}
+      {...props}
+    />
+  </DialogPortal>
+));
+
+DialogContent.displayName = "DialogContent";
+
+export const DialogHeader = ({ className, ...props }: React.HTMLAttributes<HTMLDivElement>) => (
+  <div className={cn("flex flex-col gap-1.5 text-center sm:text-left", className)} {...props} />
+);
+
+export const DialogFooter = ({ className, ...props }: React.HTMLAttributes<HTMLDivElement>) => (
+  <div className={cn("mt-5 flex flex-col-reverse gap-2 sm:flex-row sm:justify-end", className)} {...props} />
+);
+
+export const DialogTitle = React.forwardRef<
+  React.ElementRef<typeof DialogPrimitive.Title>,
+  React.ComponentPropsWithoutRef<typeof DialogPrimitive.Title>
+>(({ className, ...props }, ref) => (
+  <DialogPrimitive.Title
+    ref={ref}
+    className={cn("text-lg font-semibold text-slate-900", className)}
+    {...props}
+  />
+));
+
+DialogTitle.displayName = "DialogTitle";
+
+export const DialogDescription = React.forwardRef<
+  React.ElementRef<typeof DialogPrimitive.Description>,
+  React.ComponentPropsWithoutRef<typeof DialogPrimitive.Description>
+>(({ className, ...props }, ref) => (
+  <DialogPrimitive.Description
+    ref={ref}
+    className={cn("text-sm text-slate-600", className)}
+    {...props}
+  />
+));
+
+DialogDescription.displayName = "DialogDescription";
+