feat(auth): add secure configuration and environment support

backend/hermes/app/core/security.py

@@ -3,9 +3,10 @@ from datetime import UTC, datetime, timedelta
 from jose import jwt
 from pwdlib import PasswordHash
 
+from app.core.config import settings
+
 password_hash = PasswordHash.recommended()
 
-SECRET_KEY = "CHANGE_ME"
 ALGORITHM = "HS256"
 ACCESS_TOKEN_EXPIRE_MINUTES = 60
 
@@ -26,4 +27,8 @@ def create_access_token(subject: str) -> str:
         "exp": expire,
     }
 
-    return jwt.encode(payload, SECRET_KEY, algorithm=ALGORITHM)
+    return jwt.encode(
+        payload,
+        settings.secret_key,
+        algorithm=ALGORITHM,
+    )