Better Readonly Type Management

[helmturner]

The meta and bsonSchema instance properties are immutable, as are schemas in general. The types. however, do not correctly reflect the mutability of everything. The desired behavior is as follows:

• meta and bsonSchema properties are readonly, as are all nested properties
• attempting to set meta or bsonSchema, or assign to any nested property, should be prevented by TypeScript
• The parse result types inferred by B.Type should NOT be readonly
• An object schema built from another object schema's meta.shape property should behave and be typed just like a default instance of the original schema
• There should be as few readonly or Readonly<> repetitions in the tooltip as is necessary to achieve the above goals

It may be necessary to create Meta and BsonSchema classes to achieve this in a way that is both type-safe and ergonomic.