fix(demos/ota): launch fault_manager_node so /faults endpoint responds

Without /fault_manager/* services running, the gateway's /faults endpoint
hangs waiting for the service call (default 5s timeout) and the Faults
Dashboard panel surfaces it as 503. Adds 'ros2 run ros2_medkit_fault_manager
fault_manager_node' to entrypoint.sh - the gateway image already builds
the package; we just need to run it. Defaults are fine for the demo
(SQLite at /var/lib/ros2_medkit/faults.db, snapshot capture enabled).

Author: bburda

demos/ota_nav2_sensor_fix/entrypoint.sh

@@ -15,6 +15,12 @@ source /ws/install/setup.bash
 # Demo nodes the plugin will swap (broken_lidar -> fixed_lidar) and
 # uninstall (broken_lidar_legacy). obstacle_classifier_v2 is installed
 # fresh by the demo and not started here.
+# Fault manager: serves /fault_manager/* services that the gateway's
+# /faults endpoint calls. Without it /faults hangs because the gateway
+# blocks waiting for the service. Default parameters are fine for the
+# demo (in-memory store, no persistence).
+ros2 run ros2_medkit_fault_manager fault_manager_node &
+
 ros2 run broken_lidar broken_lidar_node &
 ros2 run broken_lidar_legacy broken_lidar_legacy &