feat: require explicit runtime configuration

backend/src/kbqa/config.py

@@ -9,37 +9,39 @@ class Settings(BaseSettings):
     model_config = SettingsConfigDict(
         env_file=".env",
         env_prefix="KBQA_",
-        extra="ignore",
+        extra="forbid",
     )
 
-    app_name: str = "KBQA"
-    debug: bool = False
+    app_name: str
+    debug: bool
 
-    dashscope_api_key: str = ""
-    dashscope_base_url: str = "https://dashscope.aliyuncs.com/compatible-mode/v1"
-    chat_model: str = "qwen3.5-flash"
-    embedding_model: str = "text-embedding-v4"
-    embedding_dim: int = 1024
+    dashscope_api_key: str
+    dashscope_base_url: str
+    chat_model: str
+    embedding_model: str
+    embedding_dim: int
 
-    database_url: str = "sqlite+aiosqlite:///./data/kbqa.sqlite3"
-    milvus_uri: str = "./data/milvus/kbqa.db"
-    raw_data_dir: Path = Path("./data/raw")
+    database_url: str
+    milvus_uri: str
+    raw_data_dir: Path
 
-    chunk_size: int = Field(default=500, ge=1)
-    chunk_overlap: int = Field(default=50, ge=0)
-    retrieval_top_k: int = Field(default=5, ge=1, le=100)
-    max_research_searches: int = Field(default=3, ge=1, le=10)
-    max_sources: int = Field(default=8, ge=1, le=50)
-    history_message_limit: int = Field(default=20, ge=1, le=200)
-    max_upload_mib: int = Field(default=20, ge=1, le=1024)
-    max_query_length: int = Field(default=10_000, ge=1, le=100_000)
-    cors_origins: list[str] = [
-        "http://localhost:5173",
-        "http://127.0.0.1:5173",
-    ]
+    chunk_size: int = Field(ge=1)
+    chunk_overlap: int = Field(ge=0)
+    retrieval_top_k: int = Field(ge=1, le=100)
+    max_research_searches: int = Field(ge=1, le=10)
+    max_sources: int = Field(ge=1, le=50)
+    history_message_limit: int = Field(ge=1, le=200)
+    max_upload_mib: int = Field(ge=1, le=1024)
+    max_query_length: int = Field(ge=1, le=100_000)
+    cors_origins: list[str]
 
-    run_live_tests: bool = False
-    live_test_file: Path | None = None
+    run_live_tests: bool
+    live_test_file: Path
+
+    langsmith_tracing: bool = Field(validation_alias="LANGSMITH_TRACING")
+    langsmith_endpoint: str = Field(validation_alias="LANGSMITH_ENDPOINT")
+    langsmith_api_key: str = Field(validation_alias="LANGSMITH_API_KEY")
+    langsmith_project: str = Field(validation_alias="LANGSMITH_PROJECT")
 
     @field_validator("chunk_overlap")
     @classmethod