feat: add typing indicator with ChatBubble component

- Add ChatBubble component for reusable chat bubble styling
- Add TypingIndicator component with animated dots (. .. ...)
- Show typing indicator after 500ms delay while waiting for AI response
- Refactor ChatMessage to use ChatBubble component
- Add isWaitingForResponse state to ChatStore

apps/client/src/components/ChatBubble.tsx

@@ -0,0 +1,28 @@
+import { View, ViewStyle } from "react-native";
+import colors from "../Themes";
+
+type BubbleSide = "left" | "right";
+
+type ChatBubbleProps = {
+  side: BubbleSide;
+  children: React.ReactNode;
+  className?: string;
+  style?: ViewStyle;
+};
+
+export function ChatBubble({ side, children, className = "", style }: ChatBubbleProps) {
+  const borderColor = side === "left" ? colors.chatBot : colors.primeFg;
+  const sideClass =
+    side === "left"
+      ? "self-start ml-2 rounded-bl-sm"
+      : "self-end mr-2 rounded-br-sm";
+
+  return (
+    <View
+      className={`bg-white border-2 border-solid rounded-xl my-2 ${sideClass} ${className}`}
+      style={[{ borderColor, elevation: 8 }, style]}
+    >
+      {children}
+    </View>
+  );
+}