add frontend application structure with authentication, generation features, and integration tests

frontend/app/config.py

@@ -0,0 +1,9 @@
+"""Flask frontend configuration."""
+import os
+
+
+class Config:
+    SECRET_KEY = os.getenv("FLASK_SECRET_KEY", "dev-secret-change-in-production")
+    BACKEND_URL = os.getenv("BACKEND_URL", "http://localhost:8000")
+    SESSION_COOKIE_HTTPONLY = True
+    SESSION_COOKIE_SAMESITE = "Lax"