feat: add Jetson 25W Studio evidence fixture

[hyeokjun32]

Summary

• Added a compact Jetson Orin Nano TensorRT FP16 25W Runtime evidence fixture.
• Connected Load Demo Evidence to return Jetson evidence track metadata for Local Studio.
• Updated Studio UI/test coverage to surface power mode, p95 latency, tegrastats status, and source path.

Validation

• poetry run python3 -m pytest tests/test_studio_routes.py -q
• poetry run python3 -m pytest -q

Impact

• Makes Local Studio demo evidence reflect measured Jetson Runtime behavior.
• Keeps Jetson work scoped as validation evidence, not a production inference service.

Notes

• 15W power-mode test is pending because the Jetson SSH account requires sudo password for nvpmodel changes.