fix: preserve v prefix in Pages model paths

[chenmohan123]

Summary

• stage Pages model assets under the SDK's existing models/v<version> URL contract
• keep both historical v1.0.0 and current v1.0.1 model directories
• add a regression test that reproduces the deployed manifest 404

Verification

• RED: expected v1.0.0/manifest.json was missing
• GREEN: targeted Pages staging contract passed
• pnpm release:test (19/19)
• targeted Prettier check
• git diff --check