Unify keyword-based widgets and pluggable widgets via a registry-driven engine. Use BSON templates extracted from each project's installed .mpk files so the output matches the project's exact Mendix and Data Widgets version, eliminating embedded-template drift. Covers the widgets shipped out of the box with an empty Mendix 11+ project (DataGrid 2, Gallery, ComboBox, filter widgets, Image). Umbrella: #529 (Unified Schema Registry).