Add uuidString, resolvedNamespace, and sourceNamespaceString to the CommandContext in api.h, as specified in the design. Have the host resolve them before calling run, using the view adapter for resolvedNamespace, and expose them in the SDK. The echo extension returns the context it received.
Tests (jstest, standalone and sharded):

• The context is correct for a collection, a collection in another database, a view, and a view on a view.
• A missing namespace gives an empty UUID on both topologies.
• A timeseries target is rejected before run is called.
• Other resolution errors are returned to the user.