fix: OpenClaw migration now shows dry-run preview before executing (#6769)

The setup wizard's OpenClaw migration previously ran immediately with
aggressive defaults (overwrite=True, preset=full) after a single
'Would you like to import?' prompt. This caused several problems:

- Config values with different semantics (e.g. tool_call_execution:
  'auto' in OpenClaw vs 'off' for Hermes yolo mode) were imported
  without translation
- Gateway tokens were hijacked from OpenClaw without warning, taking
  over Telegram/Slack/Discord channels
- Instruction files (.md) containing OpenClaw-specific setup/restart
  procedures were copied, causing Hermes restart failures

Now the migration:
1. Asks 'Would you like to see what can be imported?' (softer framing)
2. Runs a dry-run preview showing everything that would be imported
3. Displays categorized warnings for high-impact items (gateway
   takeover, config value differences, instruction files)
4. Asks for explicit confirmation with default=No
5. Executes with overwrite=False (preserves existing Hermes config)

Also extracts _load_openclaw_migration_module() for reuse and adds
_print_migration_preview() with keyword-based warning detection.

Tests updated for two-phase behavior + new test for decline-after-preview.

tests/hermes_cli/test_setup_openclaw_migration.py

@@ -44,7 +44,7 @@ class TestOfferOpenclawMigration:
             assert setup_mod._offer_openclaw_migration(tmp_path / ".hermes") is False
 
     def test_runs_migration_when_user_accepts(self, tmp_path):
-        """Should dynamically load the script and run the Migrator."""
+        """Should run dry-run preview first, then execute after confirmation."""
         openclaw_dir = tmp_path / ".openclaw"
         openclaw_dir.mkdir()
 
@@ -60,6 +60,7 @@ class TestOfferOpenclawMigration:
         fake_migrator = MagicMock()
         fake_migrator.migrate.return_value = {
             "summary": {"migrated": 3, "skipped": 1, "conflict": 0, "error": 0},
+            "items": [{"kind": "config", "status": "migrated", "destination": "/tmp/x"}],
             "output_dir": str(hermes_home / "migration"),
         }
         fake_mod.Migrator = MagicMock(return_value=fake_migrator)
@@ -70,6 +71,7 @@ class TestOfferOpenclawMigration:
         with (
             patch("hermes_cli.setup.Path.home", return_value=tmp_path),
             patch.object(setup_mod, "_OPENCLAW_SCRIPT", script),
+            # Both prompts answered Yes: preview offer + proceed confirmation
             patch.object(setup_mod, "prompt_yes_no", return_value=True),
             patch.object(setup_mod, "get_config_path", return_value=config_path),
             patch("importlib.util.spec_from_file_location") as mock_spec_fn,
@@ -91,13 +93,75 @@ class TestOfferOpenclawMigration:
         fake_mod.resolve_selected_options.assert_called_once_with(
             None, None, preset="full"
         )
-        fake_mod.Migrator.assert_called_once()
-        call_kwargs = fake_mod.Migrator.call_args[1]
-        assert call_kwargs["execute"] is True
-        assert call_kwargs["overwrite"] is True
-        assert call_kwargs["migrate_secrets"] is True
-        assert call_kwargs["preset_name"] == "full"
-        fake_migrator.migrate.assert_called_once()
+        # Migrator called twice: once for dry-run preview, once for execution
+        assert fake_mod.Migrator.call_count == 2
+
+        # First call: dry-run preview (execute=False, overwrite=True to show all)
+        preview_kwargs = fake_mod.Migrator.call_args_list[0][1]
+        assert preview_kwargs["execute"] is False
+        assert preview_kwargs["overwrite"] is True
+        assert preview_kwargs["migrate_secrets"] is True
+        assert preview_kwargs["preset_name"] == "full"
+
+        # Second call: actual execution (execute=True, overwrite=False to preserve)
+        exec_kwargs = fake_mod.Migrator.call_args_list[1][1]
+        assert exec_kwargs["execute"] is True
+        assert exec_kwargs["overwrite"] is False
+        assert exec_kwargs["migrate_secrets"] is True
+        assert exec_kwargs["preset_name"] == "full"
+
+        # migrate() called twice (once per Migrator instance)
+        assert fake_migrator.migrate.call_count == 2
+
+    def test_user_declines_after_preview(self, tmp_path):
+        """Should return False when user sees preview but declines to proceed."""
+        openclaw_dir = tmp_path / ".openclaw"
+        openclaw_dir.mkdir()
+
+        hermes_home = tmp_path / ".hermes"
+        hermes_home.mkdir()
+        config_path = hermes_home / "config.yaml"
+        config_path.write_text("agent:\n  max_turns: 90\n")
+
+        fake_mod = ModuleType("openclaw_to_hermes")
+        fake_mod.resolve_selected_options = MagicMock(return_value={"soul", "memory"})
+        fake_migrator = MagicMock()
+        fake_migrator.migrate.return_value = {
+            "summary": {"migrated": 3, "skipped": 0, "conflict": 0, "error": 0},
+            "items": [{"kind": "config", "status": "migrated", "destination": "/tmp/x"}],
+        }
+        fake_mod.Migrator = MagicMock(return_value=fake_migrator)
+
+        script = tmp_path / "openclaw_to_hermes.py"
+        script.write_text("# placeholder")
+
+        # First prompt (preview): Yes, Second prompt (proceed): No
+        prompt_responses = iter([True, False])
+
+        with (
+            patch("hermes_cli.setup.Path.home", return_value=tmp_path),
+            patch.object(setup_mod, "_OPENCLAW_SCRIPT", script),
+            patch.object(setup_mod, "prompt_yes_no", side_effect=prompt_responses),
+            patch.object(setup_mod, "get_config_path", return_value=config_path),
+            patch("importlib.util.spec_from_file_location") as mock_spec_fn,
+        ):
+            mock_spec = MagicMock()
+            mock_spec.loader = MagicMock()
+            mock_spec_fn.return_value = mock_spec
+
+            def exec_module(mod):
+                mod.resolve_selected_options = fake_mod.resolve_selected_options
+                mod.Migrator = fake_mod.Migrator
+
+            mock_spec.loader.exec_module = exec_module
+
+            result = setup_mod._offer_openclaw_migration(hermes_home)
+
+        assert result is False
+        # Only dry-run Migrator was created, not the execute one
+        assert fake_mod.Migrator.call_count == 1
+        preview_kwargs = fake_mod.Migrator.call_args[1]
+        assert preview_kwargs["execute"] is False
 
     def test_handles_migration_error_gracefully(self, tmp_path):
         """Should catch exceptions and return False."""