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">