Add metrics collection scheduler with automatic job management, improve terminal session cleanup on 404/403 errors, and refactor metrics collection endpoint to use shared background job function with WebSocket broadcast support

tests/backend/test_routes_metrics.py

@@ -105,6 +105,21 @@ class TestSetCollectionSchedule:
         data = response.json()
         assert data["interval"] == "30min"
 
+    @pytest.mark.asyncio
+    async def test_set_schedule_triggers_reschedule(self, client: AsyncClient):
+        """Le changement d'intervalle doit rescheduler le job de collecte."""
+        with patch(
+            "app.routes.metrics.apply_interval_using_global_scheduler",
+            autospec=True,
+        ) as mock_apply:
+            response = await client.post(
+                "/api/metrics/collection-schedule",
+                json={"interval": "5min"}
+            )
+
+        assert response.status_code == 200
+        mock_apply.assert_called_once_with("5min")
+
     @pytest.mark.asyncio
     async def test_set_schedule_off(self, client: AsyncClient):
         """Désactivation de la collecte."""