feat: add release-to-move TCP gizmo control in Webots

Add a native Webots marker for setting the active tool's TCP position and
orientation. Dragging edits the preview; releasing the mouse submits one
complete, checked joint trajectory with configured TCP speed limits.
Unreachable targets reset the marker to the current TCP.

Preserve coordinate, joint, and control-file commands through motion
reservations and a controller action proxy. Give the gizmo lowest priority
and finish its committed trajectory before dispatching queued regular
commands, including waits longer than the former two-second service timeout.

Place the patron TCP at its working end, 55.2 mm along local Z, and use the
flange TCP when no tool is attached. Add digital_twin.tcp_gizmo configuration,
ROS interfaces, launch integration, and regression coverage.

Document operation, configuration, tool attachment, speed limits, and
troubleshooting in both Russian and English.

Validation: 42 Python tests and 8 C++ tests passed. Webots regressions covered
one action per release, translation and rotation with and without a tool,
unreachable targets, and ordinary commands waiting for gizmo completion.

src/iiwa_bringup/launch/supported/webots_spawn.launch.py

@@ -22,6 +22,7 @@ def _spawn_setup(context, *args, **kwargs):
     world = LaunchConfiguration("world").perform(context)
     controller = LaunchConfiguration("controller").perform(context)
     initial_positions_file = LaunchConfiguration("initial_positions_file").perform(context)
+    gizmo_enabled = LaunchConfiguration("tcp_gizmo_enabled", default="false").perform(context) == "true"
 
     robot_description = converter.load_robot_description(
         model_path=description,
@@ -64,6 +65,10 @@ def _spawn_setup(context, *args, **kwargs):
 
     driver = WebotsController(
         robot_name=robot_name,
+        remappings=[
+            ('/iiwa_arm_controller/joint_trajectory', '/cobot/tcp_gizmo/controller_command'),
+            ('/iiwa_arm_controller/follow_joint_trajectory', '/cobot/tcp_gizmo/follow_joint_trajectory'),
+        ] if gizmo_enabled else [],
         parameters=[
             {"use_sim_time": True},  # dict → triggers --ros-args prefix
             params_file,             # file → --params-file (robot_description + controllers)