Ship portable CPU dispatch and verified shared runtime dependencies

.gitignore

@@ -9,7 +9,10 @@ __pycache__/
 /apps/desktop/src-tauri/gen/
 /apps/desktop/src-tauri/resources/searchi-gemma-worker*
 /apps/desktop/src-tauri/resources/vulkan-1.dll
+/apps/desktop/src-tauri/resources/*.dll
+/apps/desktop/src-tauri/resources/runtime-libraries.json
 /apps/desktop/src-tauri/resources/VULKAN-LICENSE.txt
+/apps/desktop/src-tauri/resources/MSVC-REDISTRIBUTION.txt
 /apps/desktop/src-tauri/resources/embeddinggemma2/
 /apps/desktop/src-tauri/resources/media-runtime/bin/
 /apps/desktop/src-tauri/icons/android/