-`app/MindWork AI Studio/Settings/DataModel/DataChat.cs`
## User Impact
Older settings files store default chat data source options in the nested `DataChat.PreselectedDataSourceOptions` object.
Without this shim, those defaults would be lost after upgrading to a version that exposes the individual data source default fields to configuration plugins.
## Compatibility Behavior
`DataChat.PreselectedDataSourceOptions` remains available as a compatibility property. Reading it maps the new individual fields into a `DataSourceOptions` object, and setting it copies values from the legacy nested object into the new fields.
`PreselectedDataSourcesRetrievalMode` came later than the other individual fields and is mapped the same way. A legacy-nested object never carried it, so setting the property from one gives semantic search, the default of both fields.
This lets older settings files load without a settings version migration and keeps existing UI bindings working while configuration plugins manage the individual fields.
- Confirm supported settings files are expected to contain `PreselectedDataSourcesDisabled`, `PreselectedDataSourcesAutomaticSelection`, `PreselectedDataSourcesAutomaticValidation`, `PreselectedDataSourcesRetrievalMode`, and `PreselectedDataSourceIds`.
