refactor: 将 WebUI 源码纳入仓库,移除打包产物

- 新增 webui/ 前端源码目录（React+Vite+TypeScript+Tailwind）
- 删除 api/webui/ 中旧的打包静态资源
- 更新 .gitignore 忽略 api/webui/ 构建输出和 webui/node_modules
- 更新 README 增加前端构建说明

webui/src/components/ui/input.tsx

@@ -0,0 +1,24 @@
+import * as React from 'react'
+import { cn } from '@/lib/utils'
+
+export interface InputProps
+  extends React.InputHTMLAttributes<HTMLInputElement> {}
+
+const Input = React.forwardRef<HTMLInputElement, InputProps>(
+  ({ className, type, ...props }, ref) => {
+    return (
+      <input
+        type={type}
+        className={cn(
+          'flex h-9 w-full rounded-md border border-cyber-border-DEFAULT bg-cyber-bg-tertiary px-3 py-2 text-sm font-mono text-cyber-text-primary ring-offset-background file:border-0 file:bg-transparent file:text-sm file:font-medium file:text-foreground placeholder:text-cyber-text-muted focus-visible:outline-none focus-visible:border-cyber-neon-cyan focus-visible:shadow-[0_0_10px_rgb(var(--cyber-neon-cyan)/0.2)] disabled:cursor-not-allowed disabled:opacity-50 transition-all',
+          className
+        )}
+        ref={ref}
+        {...props}
+      />
+    )
+  }
+)
+Input.displayName = 'Input'
+
+export { Input }