Refactor code structure for improved readability and maintainability

app/config.py

@@ -0,0 +1,45 @@
+from pydantic_settings import BaseSettings, SettingsConfigDict
+
+
+class Settings(BaseSettings):
+    model_config = SettingsConfigDict(env_file=".env", env_file_encoding="utf-8", extra="ignore")
+
+    app_name: str = "reader-api"
+    app_env: str = "development"
+
+    database_url: str
+    mongodb_uri: str
+
+    google_client_id: str = ""
+    nextauth_secret: str = ""
+    mobile_jwt_secret: str = ""
+
+    cors_origins: str = "*"
+    r2_account_id: str = ""
+    r2_access_key_id: str = ""
+    r2_secret_access_key: str = ""
+    r2_bucket_name: str = ""
+    r2_public_base_url: str = ""
+
+    deepseek_key: str = ""
+    deepseek_model: str = "deepseek-chat"
+    openrouter_key: str = ""
+    openrouter_paused: str = "true"
+
+    @property
+    def google_client_id_list(self) -> list[str]:
+        raw = (self.google_client_id or "").strip()
+        if not raw:
+            return []
+        return [item.strip() for item in raw.split(",") if item.strip()]
+
+
+    @property
+    def cors_origin_list(self) -> list[str]:
+        raw = (self.cors_origins or "*").strip()
+        if raw == "*":
+            return ["*"]
+        return [item.strip() for item in raw.split(",") if item.strip()]
+
+
+settings = Settings()