fix(tui): keep default personality neutral

tests/tui_gateway/test_make_agent_provider.py

@@ -54,6 +54,44 @@ def test_make_agent_passes_resolved_provider():
         assert call_kwargs.kwargs["api_mode"] == "anthropic_messages"
 
 
+def test_make_agent_ignores_display_personality_without_system_prompt():
+    """The TUI matches the classic CLI: personality only becomes active once
+    it has been saved to agent.system_prompt."""
+
+    fake_runtime = {
+        "provider": "openrouter",
+        "base_url": "https://api.synthetic.new/v1",
+        "api_key": "sk-test",
+        "api_mode": "chat_completions",
+        "command": None,
+        "args": None,
+        "credential_pool": None,
+    }
+    fake_cfg = {
+        "agent": {
+            "system_prompt": "",
+            "personalities": {"kawaii": "sparkle system prompt"},
+        },
+        "display": {"personality": "kawaii"},
+        "model": {"default": "glm-5"},
+    }
+
+    with (
+        patch("tui_gateway.server._load_cfg", return_value=fake_cfg),
+        patch("tui_gateway.server._get_db", return_value=MagicMock()),
+        patch(
+            "hermes_cli.runtime_provider.resolve_runtime_provider",
+            return_value=fake_runtime,
+        ),
+        patch("run_agent.AIAgent") as mock_agent,
+    ):
+        from tui_gateway.server import _make_agent
+
+        _make_agent("sid-default-personality", "key-default-personality")
+
+        assert mock_agent.call_args.kwargs["ephemeral_system_prompt"] is None
+
+
 def test_probe_config_health_flags_null_sections():
     """Bare YAML keys (`agent:` with no value) parse as None and silently
     drop nested settings; probe must surface them so users can fix."""