fix: detect non-interactive TTY in setup wizard to prevent hang

hermes setup hung indefinitely on headless SSH sessions, Docker
containers, and CI/CD environments because the interactive provider
selection menu could not receive input.

Two-layer fix:
1. sys.stdin.isatty() check — auto-detects non-interactive environments
2. --non-interactive flag support — already in CLI parser, now honored

In both cases the wizard exits immediately with helpful guidance
pointing users to 'hermes config set' commands.

Closes #905

tests/hermes_cli/test_setup_noninteractive.py

@@ -0,0 +1,43 @@
+"""Tests for non-interactive setup wizard behavior."""
+import pytest
+from unittest.mock import patch, MagicMock
+
+
+def _make_args(**kwargs):
+    args = MagicMock()
+    args.non_interactive = kwargs.get("non_interactive", False)
+    args.section = kwargs.get("section", None)
+    args.reset = kwargs.get("reset", False)
+    return args
+
+
+class TestNonInteractiveSetup:
+    """Verify setup wizard exits cleanly in non-interactive environments."""
+
+    def test_non_interactive_flag_skips_wizard(self, capsys):
+        """--non-interactive flag should print help and return without hanging."""
+        from hermes_cli.setup import run_setup_wizard
+        args = _make_args(non_interactive=True)
+
+        with patch("hermes_cli.setup.ensure_hermes_home"), \
+             patch("hermes_cli.setup.load_config", return_value={}), \
+             patch("hermes_cli.setup.get_hermes_home", return_value="/tmp/.hermes"):
+            run_setup_wizard(args)
+
+        out = capsys.readouterr().out
+        assert "hermes config set" in out
+
+    def test_no_tty_skips_wizard(self, capsys):
+        """When stdin has no TTY, wizard should exit with helpful message."""
+        from hermes_cli.setup import run_setup_wizard
+        args = _make_args(non_interactive=False)
+
+        with patch("hermes_cli.setup.ensure_hermes_home"), \
+             patch("hermes_cli.setup.load_config", return_value={}), \
+             patch("hermes_cli.setup.get_hermes_home", return_value="/tmp/.hermes"), \
+             patch("sys.stdin") as mock_stdin:
+            mock_stdin.isatty.return_value = False
+            run_setup_wizard(args)
+
+        out = capsys.readouterr().out
+        assert "hermes config set" in out