Add live spatial viewers and training controls

[temiroff]

Summary

• add live depth, point-cloud, IMU, and spatial viewer controls in the editor
• add fast spatial-scene polling, bounded live shutdown, and PPO training controls
• add the portable generic viewer template and update operator documentation
• ignore generated local training run state

Why

Sensor visualization and managed training need a consistent live operator surface with explicit start, stop, camera, color, and inspection controls.

Impact

Operators can inspect and control live spatial streams and managed PPO jobs directly in the Blacknode editor.

Verification

• python -m pytest tests/test_editor_canvas_interactions.py tests/test_editor_depth_viewer.py tests/test_editor_devices_refined.py tests/test_editor_graph_run.py tests/test_editor_imu_viewer.py tests/test_editor_point_cloud_viewer.py tests/test_editor_runtime.py tests/test_editor_depth_cloud_color_modes.py tests/test_editor_live_controls.py -q (78 passed)
• python -m unittest discover -s tests (545 passed, 8 skipped)
• npm run build
• changed workflow templates validated with blacknode validate

Managed Runtime release

No Runtime release is required for this core PR because it changes the editor, editor-server orchestration, templates, tests, and documentation only. A separate Runtime 0.4.12 release is part of the coordinated publish for its own service-update fix.