feat(db): 初始化数据库并创建 APIProvider 表

- 新增 init_db.py 文件，实现数据库初始化和 APIProvider 表的创建
- 新增 dataset_generation.py 文件，定义 LLMRequest、LLMResponse 和 APIProvider 模型
- 在初始化数据库时，如果环境变量中存在 API_KEY、BASE_URL 和 MODEL_ID，会自动添加一条 APIProvider 记录

schema/dataset_generation.py

@@ -0,0 +1,51 @@
+from datetime import datetime, timezone
+from typing import Optional
+from sqlmodel import SQLModel, Relationship, Field
+
+class APIProvider(SQLModel, table=True):
+    id: Optional[int] = Field(default=None, primary_key=True)
+    base_url: str = Field(..., description="API的基础URL")
+    model_id: str = Field(..., description="API使用的模型ID")
+    api_key: Optional[str] = Field(default=None, description="用于身份验证的API密钥")
+    created_at: datetime = Field(
+        default_factory=lambda: datetime.now(timezone.utc),
+        description="记录创建时间"
+    )
+
+class LLMResponse(SQLModel):
+    timestamp: datetime  = Field(
+        default_factory=lambda: datetime.now(timezone.utc),
+        description="响应的时间戳"
+    )
+    response_id: str = Field(..., description="响应的唯一ID")
+    tokens_usage: dict = Field(default_factory=lambda: {
+        "prompt_tokens": 0,
+        "completion_tokens": 0,
+        "prompt_cache_hit_tokens": None,
+        "prompt_cache_miss_tokens": None
+    }, description="token使用信息")
+    response_content: dict = Field(default_factory=dict, description="API响应的内容")
+    total_duration: float = Field(default=0.0, description="请求的总时长，单位为秒")
+    llm_parameters: dict = Field(default_factory=lambda: {
+        "temperature": None,
+        "max_tokens": None,
+        "top_p": None,
+        "frequency_penalty": None,
+        "presence_penalty": None,
+        "seed": None
+    }, description="API的生成参数")
+
+class LLMRequest(SQLModel):
+    prompt: str = Field(..., description="发送给API的提示词") 
+    provider_id: int = Field(foreign_key="apiprovider.id")
+    provider: APIProvider = Relationship()
+    format: Optional[str] = Field(default=None, description="API响应的格式")
+    response: list[LLMResponse] = Field(default_factory=list, description="API响应列表")
+    error: Optional[list[str]] = Field(default=None, description="API请求过程中发生的错误信息")
+    total_duration: float = Field(default=0.0, description="请求的总时长，单位为秒")
+    total_tokens_usage: dict = Field(default_factory=lambda: {
+        "prompt_tokens": 0,
+        "completion_tokens": 0,
+        "prompt_cache_hit_tokens": None,
+        "prompt_cache_miss_tokens": None
+    }, description="token使用信息")