Consider removing all instance methods

Consider removing all instance methods and only have data in mode instances, ideally data should be sealed/frozen by default

This is a major architectural proposal to change JugglingDB's ORM design by removing instance methods and making data immutable. Start by examining the model definitions in lib/schema.js and lib/model.js to understand current instance methods. Look at how models are instantiated and used across adapters like mysql, postgresql, and mongodb. Determine what 'sealed/frozen by default' means in practice and assess the impact on the entire codebase.

Written by the indexing model from the issue text.