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/ToolBubble.tsx

@@ -1,5 +1,15 @@
+import { cn } from "../lib/utils";
+
 export const ToolBubble = ({ text }: { text: string }) => (
-  <div className="text-sm text-gray-500 italic px-3 py-1 self-start">
-    {text}
+  <div className="flex justify-center message-enter">
+    <div
+      className={cn(
+        "inline-flex items-center gap-1.5 px-3 py-1 rounded-full",
+        "bg-leaf-pale border border-leaf-light/50",
+        "text-xs text-leaf-dark italic",
+      )}
+    >
+      {text}
+    </div>
   </div>
 );