Publish editable JSContact starter pack

[callumalpass]

What changed

• publish mdbase.jscontact pack 2.0.1
• install the JSContact starter type with an inline, collection-owned schema snapshot
• retain the immutable 2.0.0 provision while removing it from current catalog discovery
• require catalog-listed starter types to contain editable schema.value definitions

Why

A contract should define the portable boundary without making the installed collection type inherit an immutable schema. Users can now add or reshape local fields and update the explicit mapping while the contract remains independently versioned.

Validation

• npm test
• deterministic catalog build
• transactional dry-run, install, reinstall, and implementation verification