build: package universal Windows runtime and verify automatic CPU fallback

README.md

@@ -142,6 +142,10 @@ How quickly a folder becomes searchable depends on its size and contents.
 The desktop keeps its search model warm for subsequent searches.
 Use **Reindex** after adding or changing files in an indexed folder.
 
+searchi automatically chooses supported graphics acceleration when available
+and falls back to CPU when it cannot use it. You do not need a graphics
+development toolkit. Hardware and release validation are still in progress.
+
 ## Private by design
 
 You choose the folders to index. By default, file contents, previews and search