Frontend revamp: Animal Crossing × Claude design with shadcn components

- New palette: deep nook green sidebar, sage user bubbles, warm cream answer cards
- shadcn-style UI primitives: Button (CVA variants), Textarea, Input, Badge, Table
- cn() utility (clsx + tailwind-merge)
- lucide-react icons throughout (no more text-only buttons)
- Simba mode: custom CSS toggle switch
- Send button: circular amber button with arrow icon
- AnswerBubble: amber gradient accent bar, loading dots animation
- QuestionBubble: sage green pill with rounded-3xl
- ToolBubble: centered leaf-green badge pill
- ConversationList: active item highlighting, proper selectedId prop
- Sidebar: collapsible with PanelLeftClose/Open icons, icon-only collapsed state
- LoginScreen: decorative background blobs, refined rounded card
- AdminPanel: proper icon buttons, leaf-green save confirmation
- Fonts: Playfair Display (brand) + Nunito 800 weight added

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

raggr-frontend/src/components/ui/button.tsx

@@ -0,0 +1,48 @@
+import { cva, type VariantProps } from "class-variance-authority";
+import { cn } from "../../lib/utils";
+
+const buttonVariants = cva(
+  "inline-flex items-center justify-center gap-2 whitespace-nowrap rounded-xl text-sm font-semibold transition-all duration-200 disabled:pointer-events-none disabled:opacity-50 cursor-pointer select-none",
+  {
+    variants: {
+      variant: {
+        default:
+          "bg-leaf text-white shadow-sm shadow-leaf/20 hover:bg-leaf-dark hover:shadow-md hover:shadow-leaf/30 active:scale-[0.97]",
+        amber:
+          "bg-amber-glow text-white shadow-sm shadow-amber/20 hover:bg-amber-dark hover:shadow-md active:scale-[0.97]",
+        ghost:
+          "text-cream/70 hover:text-cream hover:bg-white/8 active:scale-[0.97]",
+        "ghost-dark":
+          "text-warm-gray hover:text-charcoal hover:bg-sand-light/60 active:scale-[0.97]",
+        outline:
+          "border border-sand bg-transparent text-warm-gray hover:bg-cream-dark hover:text-charcoal active:scale-[0.97]",
+        destructive:
+          "text-red-400 hover:text-red-600 hover:bg-red-50 active:scale-[0.97]",
+      },
+      size: {
+        default: "h-9 px-4 py-2",
+        sm: "h-7 px-3 text-xs",
+        lg: "h-11 px-6 text-base",
+        icon: "h-9 w-9",
+        "icon-sm": "h-7 w-7",
+      },
+    },
+    defaultVariants: {
+      variant: "default",
+      size: "default",
+    },
+  },
+);
+
+export interface ButtonProps
+  extends React.ButtonHTMLAttributes<HTMLButtonElement>,
+    VariantProps<typeof buttonVariants> {}
+
+export const Button = ({ className, variant, size, ...props }: ButtonProps) => {
+  return (
+    <button
+      className={cn(buttonVariants({ variant, size }), className)}
+      {...props}
+    />
+  );
+};