fix(tailwind): add missing shadcn/ui color mappings for opaque dialog backgrounds

The dialog backgrounds were transparent because Tailwind 3 requires explicit
color mappings in the config to use CSS variables. Added standard shadcn/ui
color mappings (background, foreground, card, primary, etc.) and removed
unnecessary overlayClassName overrides from dialog components.

src/components/ConfirmDialog.tsx

@@ -40,11 +40,7 @@ export function ConfirmDialog({
         }
       }}
     >
-      <DialogContent
-        className="max-w-sm"
-        zIndex="alert"
-        overlayClassName="bg-background/80"
-      >
+      <DialogContent className="max-w-sm" zIndex="alert">
         <DialogHeader className="space-y-3 border-b-0 bg-transparent pb-0">
           <DialogTitle className="flex items-center gap-2 text-lg font-semibold">
             <AlertTriangle className="h-5 w-5 text-destructive" />

src/components/mcp/McpWizardModal.tsx

@@ -228,7 +228,6 @@ const McpWizardModal: React.FC<McpWizardModalProps> = ({
       <DialogContent
         className="max-w-2xl max-h-[90vh] flex flex-col"
         zIndex="alert"
-        overlayClassName="bg-background/80"
       >
         <DialogHeader className="space-y-3 border-b-0 bg-transparent pb-0">
           <DialogTitle className="text-lg font-semibold">

tailwind.config.js

@@ -8,6 +8,40 @@ export default {
   theme: {
     extend: {
       colors: {
+        // shadcn/ui CSS 变量映射
+        background: "hsl(var(--background))",
+        foreground: "hsl(var(--foreground))",
+        card: {
+          DEFAULT: "hsl(var(--card))",
+          foreground: "hsl(var(--card-foreground))",
+        },
+        popover: {
+          DEFAULT: "hsl(var(--popover))",
+          foreground: "hsl(var(--popover-foreground))",
+        },
+        primary: {
+          DEFAULT: "hsl(var(--primary))",
+          foreground: "hsl(var(--primary-foreground))",
+        },
+        secondary: {
+          DEFAULT: "hsl(var(--secondary))",
+          foreground: "hsl(var(--secondary-foreground))",
+        },
+        muted: {
+          DEFAULT: "hsl(var(--muted))",
+          foreground: "hsl(var(--muted-foreground))",
+        },
+        accent: {
+          DEFAULT: "hsl(var(--accent))",
+          foreground: "hsl(var(--accent-foreground))",
+        },
+        destructive: {
+          DEFAULT: "hsl(var(--destructive))",
+          foreground: "hsl(var(--destructive-foreground))",
+        },
+        border: "hsl(var(--border))",
+        input: "hsl(var(--input))",
+        ring: "hsl(var(--ring))",
         // macOS 风格系统蓝
         blue: {
           400: '#409CFF',