Release v4.28.0

Added

• SchemaEditor tree layout: a "Generated" toggle that marks a property with x-generated: true. Hosts offer it with allowGeneratedProperty (a flag or a per-property predicate), or with onSetGeneratedProperty in controlled mode. Its labels can be overridden through labels, and it is styled through the generated part. (#425)
• A generated property shows a read-only marker when the toggle is not offered, for example in readOnly mode. Schemas that already contain x-generated: true show this marker without any host change. (#425)
• Property.isGenerated, Property.vendorKeywords, Property.itemVendorKeywords and the GENERATED_KEYWORD constant. (#425)

Fixed

• The tree layout keeps every x- vendor keyword when the schema is edited: on properties, on array items and in nested objects. Root keywords, definitions and other root keys are kept, and so is the original key order. Before this, only x-concept and x-key survived an edit. Changing a property's type drops the annotations of its old array items. (#425)