feat(trainer): add GitHub activity heatmap, 4-option quiz mode, active typing, and duplicate checks

app/config.py

@@ -27,6 +27,8 @@ DEBUG = os.getenv("DEBUG", "False").lower() in ("1", "true", "yes")
 SECRET_KEY = os.getenv("SECRET_KEY", "default-dev-secret-key-please-change-in-production")
 SESSION_COOKIE_NAME = os.getenv("SESSION_COOKIE_NAME", "notes_session")
 SESSION_EXPIRE_DAYS = int(os.getenv("SESSION_EXPIRE_DAYS", "30"))
+SESSION_MAX_AGE = SESSION_EXPIRE_DAYS * 86400
+
 
 RATE_LIMIT_LOGIN_MAX = int(os.getenv("RATE_LIMIT_LOGIN_MAX", "5"))
 RATE_LIMIT_LOGIN_WINDOW_SEC = int(os.getenv("RATE_LIMIT_LOGIN_WINDOW_SEC", "60"))