feat(guardrails): añade NeMo stub, CompositeEngine paralelo y factory

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tests/unit/test_guardrails_composite.py

@@ -0,0 +1,44 @@
+"""Tests del CompositeGuardrailEngine."""
+
+from uuid import uuid4
+
+import pytest
+
+from agentforge_core.domain.policy import PolicyDefinition
+from agentforge_core.guardrails.composite import CompositeGuardrailEngine
+from agentforge_core.guardrails.guardrails_ai import GuardrailsAIEngine
+from agentforge_core.guardrails.nemo import NeMoGuardrailsEngine
+
+
+@pytest.fixture
+def policy() -> PolicyDefinition:
+    return PolicyDefinition(
+        name="t",
+        version="v1",
+        description="t",
+        input_validators=[],
+        output_validators=[],
+    )
+
+
+async def test_composite_agrega_violaciones_de_todos(policy: PolicyDefinition) -> None:
+    engine = CompositeGuardrailEngine(
+        [GuardrailsAIEngine(), NeMoGuardrailsEngine(allowed_keywords=["sip"])]
+    )
+    violations = await engine.validate_input("texto sin tema", policy, uuid4())
+    assert isinstance(violations, list)
+    # NeMo debe marcar off-topic (warning, no bloqueo)
+    assert any(v.validator == "NeMoTopicalRails" for v in violations)
+
+
+async def test_composite_no_agrega_si_match_topic(policy: PolicyDefinition) -> None:
+    engine = CompositeGuardrailEngine(
+        [GuardrailsAIEngine(), NeMoGuardrailsEngine(allowed_keywords=["sip"])]
+    )
+    violations = await engine.validate_input("incidente sip en cscf", policy, uuid4())
+    assert not [v for v in violations if v.validator == "NeMoTopicalRails"]
+
+
+def test_composite_rechaza_lista_vacia() -> None:
+    with pytest.raises(ValueError):
+        CompositeGuardrailEngine([])