feat(image): prepare WanGP models with observable progress

[georgi]

Summary

• add a short-lived WanGP model-preparation adapter without modifying upstream WanGP
• report filesystem growth, process write activity, rate, free space, active files, and explicit stalls
• pin the compatible nodetool-core worker revision in the combined image
• keep WanGP isolated in its own interpreter and preserve the non-commercial distribution boundary

Validation

• ruff check .
• ty check .
• pytest -q (123 passed)
• source-boundary grep returned no matches