refactor: raise error on auth failure and clean up meeks-ai fallback

tests/test_client.py

@@ -122,3 +122,14 @@ def test_gitea_client_list_unread_notifications() -> None:
         assert kwargs.get("params") == {"all": "false", "since": "2026-06-30T21:41:16+02:00"}
 
 
+import pytest
+
+def test_gitea_client_get_authenticated_user_failure() -> None:
+    client: GiteaClient = GiteaClient()
+    with patch("httpx.Client.get") as mock_get:
+        mock_get.side_effect = Exception("Connection error")
+        with pytest.raises(RuntimeError, match="Could not get authenticated user"):
+            client.get_authenticated_user()
+
+
+