fix(ui): [UI7-2] 统一全局 Design Tokens，移除冗余字体，修复异常色值引用

client/src/components/ui/button.tsx

@@ -4,15 +4,15 @@ import { cva, type VariantProps } from "class-variance-authority";
 import { cn } from "../../lib/utils";
 
 const buttonVariants = cva(
-  "inline-flex items-center justify-center whitespace-nowrap rounded-lg text-sm font-medium transition-colors focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-primary-200 disabled:pointer-events-none disabled:opacity-50",
+  "inline-flex items-center justify-center whitespace-nowrap rounded-lg text-sm font-medium transition-colors focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-zinc-300 disabled:pointer-events-none disabled:opacity-50",
   {
     variants: {
       variant: {
-        default: "bg-primary text-white hover:bg-primary-600",
-        secondary: "border border-slate-200 bg-white text-slate-700 hover:bg-slate-50",
-        outline: "border border-slate-200 bg-transparent text-slate-900 hover:bg-slate-50",
+        default: "bg-primary text-white hover:bg-primary-light",
+        secondary: "border border-zinc-200 bg-white text-zinc-700 hover:bg-zinc-50",
+        outline: "border border-zinc-200 bg-transparent text-zinc-900 hover:bg-zinc-50",
         destructive: "bg-red-600 text-white hover:bg-red-700",
-        ghost: "bg-transparent text-slate-700 hover:bg-slate-100",
+        ghost: "bg-transparent text-zinc-700 hover:bg-zinc-100",
         link: "bg-transparent text-primary underline-offset-4 hover:underline",
       },
       size: {