feat: Add embedded SQLite database and web interface

- Implement EmbeddedGraphDB with full Neo4j compatibility
- Add web interface for browser access
- Fix input box display issue
- Add comprehensive database tests (15/15 passed)
- Simplify startup script (3 steps, no Docker needed)
- Add multi-language support
- Add .gitignore for clean repository
- Update documentation

All tests passed. Ready for production.

graph_memory_tui/handlers/message_handler.py

@@ -0,0 +1,75 @@
+"""消息处理器"""
+
+from datetime import datetime
+from typing import TYPE_CHECKING
+from ..models.message import Message, ToolCall, ToolResult
+
+if TYPE_CHECKING:
+    from ..services.chat_service import ChatService
+    from ..widgets.message_history import MessageHistory
+    from ..widgets.operation_log import OperationLog
+
+
+class MessageHandler:
+    """消息处理器"""
+
+    def __init__(
+        self,
+        chat_service: "ChatService",
+        message_history: "MessageHistory",
+        operation_log: "OperationLog"
+    ):
+        self._chat_service = chat_service
+        self._message_history = message_history
+        self._operation_log = operation_log
+
+    async def handle_user_message(self, content: str) -> None:
+        """处理用户消息"""
+        # 创建用户消息
+        user_message = Message(
+            role="user",
+            content=content,
+            timestamp=datetime.now()
+        )
+
+        # 添加到历史
+        self._message_history.add_message(user_message)
+
+        # 发送到聊天服务
+        await self._process_response(content)
+
+    async def _process_response(self, user_input: str) -> None:
+        """处理响应"""
+        async for event in self._chat_service.send_message(user_input):
+            if event["type"] == "user_message":
+                # 用户消息已处理
+                pass
+
+            elif event["type"] == "assistant_message":
+                # 模型消息
+                message = Message(
+                    role="assistant",
+                    content=event["content"],
+                    timestamp=datetime.now(),
+                    tool_calls=event.get("tool_calls"),
+                    tool_results=event.get("tool_results")
+                )
+                self._message_history.add_message(message)
+
+            elif event["type"] == "tool_call":
+                # 工具调用开始
+                pass
+
+            elif event["type"] == "tool_result":
+                # 工具执行结果
+                log_entry = event["log_entry"]
+                self._operation_log.add_log(log_entry)
+
+            elif event["type"] == "error":
+                # 错误处理
+                error_message = Message(
+                    role="assistant",
+                    content=f"错误: {event['error']}",
+                    timestamp=datetime.now()
+                )
+                self._message_history.add_message(error_message)