add download service

backend/app/openings_downloader/config.py

@@ -0,0 +1,24 @@
+from pydantic_settings import BaseSettings
+
+
+class DownloaderSettings(BaseSettings):
+    """Settings for the Openings Downloader module."""
+
+    # Shikimori API
+    shikimori_user_agent: str = "AnimeQuiz/1.0"
+    shikimori_token: str = ""  # Optional OAuth token for higher rate limits
+
+    # S3 Storage limit (100 GB default)
+    s3_storage_limit_bytes: int = 107_374_182_400  # 100 GB
+
+    # Download settings
+    download_timeout_seconds: int = 300
+    default_estimated_size_bytes: int = 6_291_456  # 6 MB default for unknown files
+
+    class Config:
+        env_prefix = "DOWNLOADER_"
+        env_file = ".env"
+        extra = "ignore"
+
+
+downloader_settings = DownloaderSettings()