feat(chat): implement initial chatbot UI and functionality

This commit introduces the foundational user-facing chatbot interface.

- Adds a new `ChatbotPage` component with a complete UI for displaying messages, user input, and a simulated bot response.
- Implements a "typing" indicator for a better user experience.
- Integrates `react-router-dom` to handle application routing, directing the root path to the new chatbot and moving the admin login to `/admin`.
- Adds `react-icons` as a new dependency for UI elements.
- Extends Tailwind CSS theme with new colors and adds custom CSS for the typing animation.

adventure-rental-app/package.json

@@ -13,6 +13,7 @@
     "axios": "^1.11.0",
     "react": "^19.1.0",
     "react-dom": "^19.1.0",
+    "react-icons": "^5.5.0",
     "react-router-dom": "^7.7.1"
   },
   "devDependencies": {