First attempt to tink demo

src/config.py

@@ -0,0 +1,25 @@
+"""
+App configuration loaded from environment / .env file.
+"""
+
+import os
+from functools import lru_cache
+from dotenv import load_dotenv
+
+load_dotenv()
+
+
+class Settings:
+    tink_client_id: str = os.environ["TINK_CLIENT_ID"]
+    tink_client_secret: str = os.environ["TINK_CLIENT_SECRET"]
+    tink_redirect_uri: str = os.getenv("TINK_REDIRECT_URI", "http://localhost:8000/callback")
+    app_base_url: str = os.getenv("APP_BASE_URL", "http://localhost:8000")
+    session_secret: str = os.getenv("SESSION_SECRET", "dev-only-change-in-prod")
+    tink_api_base: str = os.getenv("TINK_API_BASE", "https://api.tink.com")
+    tink_link_base: str = os.getenv("TINK_LINK_BASE", "https://link.tink.com")
+    demo_mode: bool = os.getenv("DEMO_MODE", "false").lower() in ("true", "1", "yes")
+
+
+@lru_cache
+def get_settings() -> Settings:
+    return Settings()