feat(api): implementa /executions con invoke + HITL approve/reject + persistencia

- POST /agents/{name}/invoke, GET /executions, GET /executions/{trace_id},
  POST /executions/{trace_id}/{approve,reject}.
- execution_index.json persiste trace_id → (agent_name, version) para reconstruir
  el contexto en approve/reject tras un reinicio.
- Refactor del orchestrator: split _snapshot → _build_execution + _snapshot, nuevo
  método público snapshot() (lee estado sin avanzar). Sustituye a los helpers
  _snapshot_execution/_build_graph_for_snapshot del plan, incompatibles con el
  checkpointer por-llamada.
- Aliases Annotated[...] de dependencias movidos a deps.py.
- Fixture mínima tests/fixtures/policies/default/.

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

tests/fixtures/policies/default/index.yaml

@@ -0,0 +1,8 @@
+name: default
+versions:
+  - id: v1
+    hash: testhashp1
+    author: Juan
+    message: fixture mínima
+    created_at: 2026-04-01T00:00:00Z
+active_version: v1

tests/fixtures/policies/default/versions/v1.yaml

@@ -0,0 +1,6 @@
+name: default
+version: v1
+description: Política mínima para tests del core (sin validadores)
+input_validators: []
+output_validators: []
+on_validator_error: fail_closed

tests/unit/test_api_executions.py

@@ -0,0 +1,124 @@
+"""Tests del router /executions: invoke, get, list, approve, reject."""
+
+from pathlib import Path
+
+import pytest
+from fastapi.testclient import TestClient
+
+from agentforge_core.api import deps
+from agentforge_core.main import create_app
+
+FIXTURES = Path(__file__).parent.parent / "fixtures"
+
+
+@pytest.fixture(autouse=True)
+def patch_settings(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+    monkeypatch.setenv("DATA_DIR", str(tmp_path))
+    monkeypatch.setenv("AGENTS_DIR", str(FIXTURES / "agents"))
+    monkeypatch.setenv("POLICIES_DIR", str(FIXTURES / "policies"))
+    monkeypatch.setenv("LLM_PROVIDER", "mock")
+    for fn in (
+        deps.get_settings,
+        deps.get_registry,
+        deps.get_policy_store,
+        deps.get_orchestrator,
+        deps.get_llm_provider,
+        deps.get_guardrail_engine,
+    ):
+        fn.cache_clear()
+
+
+@pytest.fixture
+def client() -> TestClient:
+    return TestClient(create_app())
+
+
+def test_invoke_devuelve_execution_completada(client: TestClient) -> None:
+    r = client.post("/agents/incident_analyzer/invoke", json={"input": "degradación MOS pool SBC"})
+    assert r.status_code == 200
+    body = r.json()
+    assert body["status"] == "completed"
+    assert body["agent_name"] == "incident_analyzer"
+    assert body["agent_version"] == "v1"
+    assert body["needs_human_for"] is None
+
+
+def test_invoke_agente_inexistente_404(client: TestClient) -> None:
+    r = client.post("/agents/inexistente/invoke", json={"input": "x"})
+    assert r.status_code == 404
+
+
+def test_invoke_riesgo_alto_pausa_hitl(client: TestClient) -> None:
+    r = client.post("/agents/incident_analyzer/invoke", json={"input": "caída registros sip"})
+    assert r.status_code == 200
+    body = r.json()
+    assert body["status"] == "awaiting_approval"
+    assert body["needs_human_for"]
+    assert {a["id"] for a in body["needs_human_for"]} == {"act-1"}
+
+
+def test_get_execution_existe_tras_invoke(client: TestClient) -> None:
+    trace_id = client.post(
+        "/agents/incident_analyzer/invoke", json={"input": "degradación MOS pool SBC"}
+    ).json()["trace_id"]
+    r = client.get(f"/executions/{trace_id}")
+    assert r.status_code == 200
+    assert r.json()["trace_id"] == trace_id
+
+
+def test_get_execution_inexistente_404(client: TestClient) -> None:
+    r = client.get("/executions/00000000-0000-0000-0000-000000000000")
+    assert r.status_code == 404
+
+
+def test_list_executions_incluye_la_completada(client: TestClient) -> None:
+    client.post("/agents/incident_analyzer/invoke", json={"input": "degradación MOS pool SBC"})
+    r = client.get("/executions")
+    assert r.status_code == 200
+    rows = r.json()
+    assert len(rows) == 1
+    assert rows[0]["status"] == "completed"
+    assert rows[0]["n_proposed_actions"] == 1
+
+
+def test_approve_resume_completa_ejecucion(client: TestClient) -> None:
+    invoked = client.post(
+        "/agents/incident_analyzer/invoke", json={"input": "caída registros sip"}
+    ).json()
+    trace_id = invoked["trace_id"]
+    action_ids = [a["id"] for a in invoked["needs_human_for"]]
+    r = client.post(
+        f"/executions/{trace_id}/approve",
+        json={"approved_action_ids": action_ids, "comment": "OK adelante"},
+    )
+    assert r.status_code == 200
+    body = r.json()
+    assert body["status"] == "completed"
+    assert {a["id"] for a in body["final_output"]["approved_actions"]} == {"act-1"}
+
+
+def test_reject_marca_failed(client: TestClient) -> None:
+    trace_id = client.post(
+        "/agents/incident_analyzer/invoke", json={"input": "caída registros sip"}
+    ).json()["trace_id"]
+    r = client.post(f"/executions/{trace_id}/reject", json={"reason": "no procede ahora"})
+    assert r.status_code == 200
+    body = r.json()
+    assert body["status"] == "failed"
+    assert "rejected_by_human" in body["error"]
+
+
+def test_approve_sobre_estado_no_pausado_da_409(client: TestClient) -> None:
+    trace_id = client.post(
+        "/agents/incident_analyzer/invoke", json={"input": "degradación MOS pool SBC"}
+    ).json()["trace_id"]
+    r = client.post(f"/executions/{trace_id}/approve", json={"approved_action_ids": []})
+    assert r.status_code == 409
+
+
+def test_approve_trace_id_desconocido_da_404(client: TestClient) -> None:
+    r = client.post(
+        "/executions/11111111-1111-1111-1111-111111111111/approve",
+        json={"approved_action_ids": []},
+    )
+    assert r.status_code == 404

tests/unit/test_runtime_orchestrator.py

@@ -2,6 +2,7 @@
 
 from datetime import UTC, datetime
 from pathlib import Path
+from uuid import uuid4
 
 import pytest
 
@@ -64,6 +65,23 @@ async def test_invoke_camino_feliz(orchestrator: AgentOrchestrator) -> None:
     ]
 
 
+async def test_snapshot_relee_estado_sin_avanzar(orchestrator: AgentOrchestrator) -> None:
+    agent = _agent()
+    paused = await orchestrator.invoke(
+        agent_def=agent, policy=_policy(), user_input="caída registros sip"
+    )
+    again = await orchestrator.snapshot(agent_def=agent, policy=_policy(), trace_id=paused.trace_id)
+    assert again is not None
+    assert again.status == "awaiting_approval"
+    assert again.trace_id == paused.trace_id
+    # Idempotente: leer no añade pasos al decision_path.
+    assert [s.step for s in again.decision_path] == [s.step for s in paused.decision_path]
+
+
+async def test_snapshot_trace_id_desconocido_devuelve_none(orchestrator: AgentOrchestrator) -> None:
+    assert await orchestrator.snapshot(agent_def=_agent(), policy=_policy(), trace_id=uuid4()) is None
+
+
 async def test_invoke_pausa_hitl_y_resume_aprueba(orchestrator: AgentOrchestrator) -> None:
     agent = _agent()
     paused = await orchestrator.invoke(