refactor: 主要功能实现

目前的工作已经实现的功能：
- 基本 FastAPI 路由；
- 基本 AI 聊天和创作功能；
- 用户信息管理、权限验证、JWT 令牌签发和验证、端点保护；
- HTML 验证码邮件发送和验证码验证。

src/nyahome/database/__init__.py

@@ -0,0 +1,44 @@
+from sqlmodel import SQLModel
+
+from .engine import engine
+from .model_aii import AiiModel, AiiModelPublic, AiiProvider, AiiProviderPublic, z_aii_model, z_aii_provider
+from .model_story import (
+    Chatroom,
+    ChatroomChat,
+    ChatroomChatAccept,
+    ChatroomChatDelete,
+    ChatroomChatEdit,
+    ChatroomPublic,
+    ChatScript,
+    ScriptTemplate,
+)
+from .model_user import ModelUploadFile, ModelUser
+from .session import async_get_session, get_session
+
+
+# 创建数据库连接和数据库文件
+def create_db() -> None:  # noqa: RUF067
+    SQLModel.metadata.create_all(engine)
+
+
+__all__ = [
+    AiiModel,
+    AiiModelPublic,
+    AiiProvider,
+    AiiProviderPublic,
+    ChatScript,
+    Chatroom,
+    ChatroomChat,
+    ChatroomChatAccept,
+    ChatroomChatDelete,
+    ChatroomChatEdit,
+    ChatroomPublic,
+    ModelUploadFile,
+    ModelUser,
+    ScriptTemplate,
+    async_get_session,
+    create_db,
+    get_session,
+    z_aii_model,
+    z_aii_provider,
+]