Make SEESWM evaluation and checkpoints fail closed

[noah-ing]

Summary

• ground the project narrative in the two checked-in exploratory artifacts and remove claims those artifacts cannot support
• add a native-type schema-v2 checkpoint format, strict reconstruction, bounded environment validation, deterministic seeds, and explicit provenance
• correct research-diagnostic math and sampling, add regression tests, and add MIT licensing, private-reporting guidance, and pinned read-only CI

Verification

• all changed and new Python sources compile
• pyproject, workflow, JSON, link, and diff checks completed during review
• prior focused schema, environment, and research-diagnostic tests passed

The local environment does not include PyTorch, so the full pytest suite on this PR is the required merge gate. No trained checkpoint or new research result is claimed.