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/stores/ChatStore.ts

@@ -13,14 +13,17 @@ export type MessageData = {
 
 interface ChatState {
   messages: MessageData[];
+  isWaitingForResponse: boolean;
   addMessages: (messages: MessageData[]) => void;
   addMessage: (message: MessageData) => void;
   updateMessage: (id: string, updates: Partial<MessageData>) => void;
   clearMessages: () => void;
+  setWaitingForResponse: (waiting: boolean) => void;
 }
 
 export const useChatStore = create<ChatState>((set) => ({
   messages: [],
+  isWaitingForResponse: false,
   addMessages(messages) {
     set((state) => ({ messages: [...state.messages, ...messages] }));
   },
@@ -37,6 +40,9 @@ export const useChatStore = create<ChatState>((set) => ({
   clearMessages: () => {
     set({ messages: [] });
   },
+  setWaitingForResponse: (waiting: boolean) => {
+    set({ isWaitingForResponse: waiting });
+  },
 }));
 
 // Helper to convert server ChatMessage to client MessageData