feat(system): configure telemetry polling per contour

tests/test_compute_contour_api.py

@@ -39,6 +39,7 @@ def test_contour_store_migrates_worker_006_as_first_configuration(
     assert len(contours) == 1
     assert contours[0].contour_id == "worker-006"
     assert contours[0].telemetry_mode == "agent-mqtt"
+    assert contours[0].telemetry_poll_interval_seconds == 3
     assert not store.path.exists()
 
 
@@ -65,10 +66,12 @@ def test_contour_store_creates_and_updates_private_catalog(tmp_path: Path) -> No
             ssh_port=22,
             mqtt_host="192.0.2.5",
             mqtt_port=1883,
+            telemetry_poll_interval_seconds=1,
         ),
     )
 
     assert updated.display_name == "Field Worker 01"
+    assert updated.telemetry_poll_interval_seconds == 1
     assert updated.revision == 1
     assert stat.S_IMODE(store.path.stat().st_mode) == 0o600
     assert len(store.list_contours()) == 2
@@ -85,6 +88,7 @@ def test_contour_store_creates_and_updates_private_catalog(tmp_path: Path) -> No
                 ssh_port=22,
                 mqtt_host="127.0.0.1",
                 mqtt_port=1883,
+                telemetry_poll_interval_seconds=3,
             ),
         )