fix: opencode config

tests/test_config.py

@@ -32,6 +32,12 @@ def test_defaults_research_variant_to_high() -> None:
     assert settings.research_variant == "high"
 
 
+def test_defaults_explore_agent_to_luna_low() -> None:
+    settings = Settings(_env_file=None)  # type: ignore[call-arg]
+    assert settings.explore_model == "openai/gpt-5.6-luna"
+    assert settings.explore_variant == "low"
+
+
 def test_reads_comma_delimited_install_scripts_from_environment(monkeypatch) -> None:
     monkeypatch.setenv("AGENTCI_INSTALL_SCRIPTS", "python,dotnet")
 
@@ -40,7 +46,9 @@ def test_reads_comma_delimited_install_scripts_from_environment(monkeypatch) ->
     assert settings.install_scripts == ["python", "dotnet"]
 
 
-@pytest.mark.parametrize("field", ["plan_model", "implement_model", "research_model"])
+@pytest.mark.parametrize(
+    "field", ["plan_model", "implement_model", "explore_model", "research_model"]
+)
 def test_requires_provider_qualified_opencode_models(field: str) -> None:
     with pytest.raises(ValidationError, match="provider/model"):
         Settings(_env_file=None, **{field: "model-only"})  # type: ignore[call-arg]