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_utils/setup.py

@@ -12,6 +12,7 @@ setup(
         ('share/' + package_name, ['package.xml']),
     ],
     install_requires=['setuptools'],
+    tests_require=['pytest'],
     zip_safe=True,
     maintainer='daniel',
     maintainer_email='grabardm@ml-dev.ru',
@@ -21,6 +22,7 @@ setup(
         'console_scripts': [
             "object_spawner = iiwa_utils.object_spawner:main",
             "camera_spawner = iiwa_utils.camera_spawner:main",
+            "tcp_gizmo_spawner = iiwa_utils.tcp_gizmo_spawner:main",
         ],
     },
 )