[TATP-233]

Summary

• treat an absolute-path checkpoint without run_config.json as a standalone file using the existing explicit no-source-run behavior, while preserving strict validation for ordinary runs and checkpoints with snapshots
• pass the selected playback device as map_location when rsl-rl loads a checkpoint, fixing CUDA-saved weights on CPU and MPS
• restore uv run demo dance without adding assets or dependencies

Linked Work

• Issue: Closes Bug: dance demo cannot load its standalone checkpoint on macOS #2557
• Parent roadmap (when applicable): none
• Roadmap declared base (when applicable): not applicable
• Milestone: none
• Base branch: main
• ADR: no new structural decision; existing sim2sim no-source-run semantics are reused

Validation

• make test-all passed on the final local head before this PR was created or updated
• Additional task-specific validation listed below

Commands actually run:

uv run pytest tests/visualization/test_interactive_playback.py
uv run demo dance
make check
make test
make test-all
uv build

Results:

• Focused playback tests: 40 passed.
• Manual macOS smoke on the default MPS device: uv run demo dance completed 1000 playback frames and video rendering with exit code 0.
• Final head 9954e648fab8af4360c683494264cbd177c49041: make test-all passed, including 2760 passed / 137 skipped / 375 deselected with coverage, plus benchmark smoke module mode 35/35 and script mode 36/36.
• Clean-source uv build on the final head: sdist and wheel both built successfully; checkpoint, motion, video, ONNX, and teaser scene runtime-asset checks returned empty lists.

Remote CI route:

• Base main: all applicable current-head checks passed for 9954e648fab8af4360c683494264cbd177c49041: CI run, documentation run.

Impact

• Backend impact: mujoco demo playback; shared rsl-rl checkpoint loading
• Platform impact: both; manually verified on macOS with MPS
• Training effect expected: no

Artifacts

• W&B: not applicable
• benchmark result: benchmark smoke passed; no performance benchmark run
• video / screenshot: local smoke video rendered successfully and intentionally not added to git or distributions
• ONNX / checkpoint: generated only by the existing demo playback path; not added to git or distributions

Checklist

• Added or updated tests where needed
• Docs reviewed; no documentation change needed for this bug fix
• Linked the driving issue
• Noted any follow-up work explicitly: none