feat: add conversation history feature to AI assistant

- Add ConversationHistory dropdown component with list of past conversations
- Add useConversations hook for fetching and managing conversations via React Query
- Implement conversation switching with proper state management
- Fix bug where reopening panel showed new greeting instead of resuming conversation
- Fix bug where selecting from history caused conversation ID to revert
- Add server-side history context loading for resumed conversations
- Add Playwright E2E tests for conversation history feature
- Add logging for debugging conversation flow

Key changes:
- AssistantPanel: manages conversation state with localStorage persistence
- AssistantChat: header with [+] New Chat and [History] buttons
- Server: skips greeting for resumed conversations, loads history context on first message
- Fixed race condition in onConversationCreated callback

server/routers/assistant_chat.py

@@ -269,18 +269,23 @@ async def assistant_chat_websocket(websocket: WebSocket, project_name: str):
                 elif msg_type == "start":
                     # Get optional conversation_id to resume
                     conversation_id = message.get("conversation_id")
+                    logger.info(f"Processing start message with conversation_id={conversation_id}")
 
                     try:
                         # Create a new session
+                        logger.info(f"Creating session for {project_name}")
                         session = await create_session(
                             project_name,
                             project_dir,
                             conversation_id=conversation_id,
                         )
+                        logger.info(f"Session created, starting...")
 
                         # Stream the initial greeting
                         async for chunk in session.start():
+                            logger.info(f"Sending chunk: {chunk.get('type')}")
                             await websocket.send_json(chunk)
+                        logger.info("Session start complete")
                     except Exception as e:
                         logger.exception(f"Error starting assistant session for {project_name}")
                         await websocket.send_json({

server/services/assistant_chat_session.py

@@ -23,6 +23,7 @@ from dotenv import load_dotenv
 from .assistant_database import (
     add_message,
     create_conversation,
+    get_messages,
 )
 
 # Load environment variables from .env file if present
@@ -178,6 +179,7 @@ class AssistantChatSession:
         self.client: Optional[ClaudeSDKClient] = None
         self._client_entered: bool = False
         self.created_at = datetime.now()
+        self._history_loaded: bool = False  # Track if we've loaded history for resumed conversations
 
     async def close(self) -> None:
         """Clean up resources and close the Claude client."""
@@ -195,10 +197,14 @@ class AssistantChatSession:
         Initialize session with the Claude client.
 
         Creates a new conversation if none exists, then sends an initial greeting.
+        For resumed conversations, skips the greeting since history is loaded from DB.
         Yields message chunks as they stream in.
         """
+        # Track if this is a new conversation (for greeting decision)
+        is_new_conversation = self.conversation_id is None
+
         # Create a new conversation if we don't have one
-        if self.conversation_id is None:
+        if is_new_conversation:
             conv = create_conversation(self.project_dir, self.project_name)
             self.conversation_id = conv.id
             yield {"type": "conversation_created", "conversation_id": self.conversation_id}
@@ -260,6 +266,7 @@ class AssistantChatSession:
         model = os.getenv("ANTHROPIC_DEFAULT_OPUS_MODEL", "claude-opus-4-5-20251101")
 
         try:
+            logger.info("Creating ClaudeSDKClient...")
             self.client = ClaudeSDKClient(
                 options=ClaudeAgentOptions(
                     model=model,
@@ -276,25 +283,35 @@ class AssistantChatSession:
                     env=sdk_env,
                 )
             )
+            logger.info("Entering Claude client context...")
             await self.client.__aenter__()
             self._client_entered = True
+            logger.info("Claude client ready")
         except Exception as e:
             logger.exception("Failed to create Claude client")
             yield {"type": "error", "content": f"Failed to initialize assistant: {str(e)}"}
             return
 
-        # Send initial greeting
-        try:
-            greeting = f"Hello! I'm your project assistant for **{self.project_name}**. I can help you understand the codebase, explain features, and answer questions about the project. What would you like to know?"
+        # Send initial greeting only for NEW conversations
+        # Resumed conversations already have history loaded from the database
+        if is_new_conversation:
+            # New conversations don't need history loading
+            self._history_loaded = True
+            try:
+                greeting = f"Hello! I'm your project assistant for **{self.project_name}**. I can help you understand the codebase, explain features, and answer questions about the project. What would you like to know?"
 
-            # Store the greeting in the database
-            add_message(self.project_dir, self.conversation_id, "assistant", greeting)
+                # Store the greeting in the database
+                add_message(self.project_dir, self.conversation_id, "assistant", greeting)
 
-            yield {"type": "text", "content": greeting}
+                yield {"type": "text", "content": greeting}
+                yield {"type": "response_done"}
+            except Exception as e:
+                logger.exception("Failed to send greeting")
+                yield {"type": "error", "content": f"Failed to start conversation: {str(e)}"}
+        else:
+            # For resumed conversations, history will be loaded on first message
+            # _history_loaded stays False so send_message() will include history
             yield {"type": "response_done"}
-        except Exception as e:
-            logger.exception("Failed to send greeting")
-            yield {"type": "error", "content": f"Failed to start conversation: {str(e)}"}
 
     async def send_message(self, user_message: str) -> AsyncGenerator[dict, None]:
         """
@@ -321,8 +338,30 @@ class AssistantChatSession:
         # Store user message in database
         add_message(self.project_dir, self.conversation_id, "user", user_message)
 
+        # For resumed conversations, include history context in first message
+        message_to_send = user_message
+        if not self._history_loaded:
+            self._history_loaded = True
+            history = get_messages(self.project_dir, self.conversation_id)
+            # Exclude the message we just added (last one)
+            history = history[:-1] if history else []
+            if history:
+                # Format history as context for Claude
+                history_lines = ["[Previous conversation history for context:]"]
+                for msg in history:
+                    role = "User" if msg["role"] == "user" else "Assistant"
+                    content = msg["content"]
+                    # Truncate very long messages
+                    if len(content) > 500:
+                        content = content[:500] + "..."
+                    history_lines.append(f"{role}: {content}")
+                history_lines.append("[End of history. Continue the conversation:]")
+                history_lines.append(f"User: {user_message}")
+                message_to_send = "\n".join(history_lines)
+                logger.info(f"Loaded {len(history)} messages from conversation history")
+
         try:
-            async for chunk in self._query_claude(user_message):
+            async for chunk in self._query_claude(message_to_send):
                 yield chunk
             yield {"type": "response_done"}
         except Exception as e: