build: package universal Windows runtime and verify automatic CPU fallback

docs/ROADMAP.md

@@ -53,6 +53,12 @@ Status: implementation started; no production release yet. Windows VM tests use
   fallback; missing Vulkan/glslc fails configuration rather than hiding GPU loss.
 - [ ] Provision release-build GPU SDKs and verify one hardware-detecting package
   per OS/architecture, including missing-driver fallback and dependency closure.
+- [x] Windows-x64 official pinned SDK copied into workspace with verified cache
+  provenance; universal CPU/Vulkan worker and embedded-frontend desktop built.
+- [x] Real Windows archive integrity, packaged decoder startup and auto-mode
+  CPU inference with a controlled no-GPU-provider registry; Google CPU parity.
+- [ ] Actual missing/incompatible GPU drivers, precision, device loss and memory
+  pressure on release hardware; native GUI and clean-machine archive launch.
 - [x] Windows desktop archive packager includes explicit runtime/helper files
   and notices, checks architecture and records per-file checksums; excludes
   model caches and user data. Controlled packaging regression tests pass.