Secondary SDR priority: C2 field, node command, dashboard section

Pairs with node-26 feat/secondary-sdr-priority. NodeRecord gains
secondary_sdr_priority (ordered; SDRs beyond OP25's run it top-down) and
secondary_sdr_running, both mirrored from the node's checkin.
PATCH /nodes/{id} accepts the priority, validates it, and sends it as a
'set_secondary_priority' MQTT command. A priority-only change never
re-pushes system config, because that restarts OP25. The node detail page
gets a 'Secondary SDRs' section (admin-editable) with enable, reorder,
save, and live Running / Waiting-for-SDR state from the checkin.

Verified: c2-core pytest 482 passed; frontend tsc --noEmit clean.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

drb-c2-core/tests/test_node_secondary_priority.py

@@ -0,0 +1,59 @@
+"""
+node-26#9 — PATCH /nodes/{id} secondary_sdr_priority.
+
+The priority must reach the node as its own MQTT command, never via a config
+re-push: a config push restarts OP25, and reordering what the spare dongles do
+must not interrupt P25 recording.
+"""
+from unittest.mock import AsyncMock, MagicMock, patch
+
+from fastapi.testclient import TestClient
+
+from app.main import app
+from app.internal.auth import require_admin_token, require_service_or_firebase_token
+from app.routers import nodes
+
+client = TestClient(app)
+
+NODE = {"node_id": "n1", "assigned_system_id": "sys-1", "hardware_preset": "rtl-sdr-v3"}
+
+
+def setup_function():
+    app.dependency_overrides[require_admin_token] = lambda: {"admin": True}
+    app.dependency_overrides[require_service_or_firebase_token] = lambda: {"admin": True}
+
+
+def teardown_function():
+    app.dependency_overrides.pop(require_admin_token, None)
+    app.dependency_overrides.pop(require_service_or_firebase_token, None)
+
+
+def _patch(body):
+    with patch.object(nodes.fstore, "doc_get", AsyncMock(side_effect=lambda c, i: NODE if c == "nodes" else {"system_id": "sys-1"})), \
+         patch.object(nodes.fstore, "doc_update", AsyncMock()) as update, \
+         patch.object(nodes.mqtt_handler, "send_command", MagicMock(return_value=True)) as command, \
+         patch.object(nodes.mqtt_handler, "push_config", MagicMock()) as push:
+        resp = client.patch("/nodes/n1", json=body)
+    return resp, update, command, push
+
+
+def test_priority_only_sends_command_and_never_repushes_config():
+    resp, update, command, push = _patch({"secondary_sdr_priority": ["ais", "adsb"]})
+    assert resp.status_code == 200
+    command.assert_called_once_with("n1", {"action": "set_secondary_priority", "priority": ["ais", "adsb"]})
+    push.assert_not_called()
+    (_, _, updates), _ = update.await_args
+    assert updates == {"secondary_sdr_priority": ["ais", "adsb"], "secondary_sdr_mode": "ais"}
+
+
+def test_empty_priority_turns_secondaries_off():
+    resp, update, command, push = _patch({"secondary_sdr_priority": []})
+    assert resp.status_code == 200
+    command.assert_called_once_with("n1", {"action": "set_secondary_priority", "priority": []})
+    (_, _, updates), _ = update.await_args
+    assert updates["secondary_sdr_mode"] == "none"
+
+
+def test_unknown_or_duplicate_modes_are_rejected():
+    assert _patch({"secondary_sdr_priority": ["adsb", "sonar"]})[0].status_code == 400
+    assert _patch({"secondary_sdr_priority": ["adsb", "adsb"]})[0].status_code == 400