Record high-dose Muon checkpoint 782 durability

[qcznlp]

Summary

• record both second-pair Muon runs at their first deeply valid checkpoint
• add immutable Hugging Face receipts with exact path, size, and digest agreement
• refresh artifact-only progress to 32/60 checkpoints
• refresh read-only W&B provenance at 8 visible valid runs

Verification

• 16 focused tests passed
• portable paper evidence audit: 2,785 files / 107,442,256 bytes / complete
• JSON validation and git diff check passed

These checkpoint receipts explicitly retain scientific_completion=false; this PR makes no partial-result claim.