restructure: move backend into backend/

backend/app/config.py

@@ -0,0 +1,36 @@
+from functools import lru_cache
+
+from pydantic_settings import BaseSettings, SettingsConfigDict
+
+
+class Settings(BaseSettings):
+    model_config = SettingsConfigDict(env_file=".env", env_file_encoding="utf-8", extra="ignore")
+
+    db_host: str = "127.0.0.1"
+    db_port: int = 3306
+    db_user: str = "root"
+    db_password: str = ""
+    db_name: str = "radius"
+
+    api_key: str = "change-me"
+    cors_origins: str = "*"
+    default_limit: int = 50
+    max_limit: int = 500
+
+    @property
+    def database_url(self) -> str:
+        from urllib.parse import quote_plus
+
+        return (
+            f"mysql+pymysql://{self.db_user}:{quote_plus(self.db_password)}"
+            f"@{self.db_host}:{self.db_port}/{self.db_name}?charset=utf8mb4"
+        )
+
+    @property
+    def cors_origin_list(self) -> list[str]:
+        return [o.strip() for o in self.cors_origins.split(",") if o.strip()]
+
+
+@lru_cache
+def get_settings() -> Settings:
+    return Settings()