docs: align workflow recovery and current Evidence contracts

native/windows/README.md

@@ -26,6 +26,29 @@ its manifest. Release CI builds both, and `prepublishOnly` rejects a missing,
 stale, mismatched, or wrong-architecture artifact. A development tarball built
 without this lane reports Windows native controls as unavailable.
 
+## Restore the artifact in a source checkout
+
+The source tree omits `native/windows/build/` from Git. To run Windows
+provider-backed workflows from a checkout without the MinGW build lane, extract
+the two files from the published `rea-agents` tarball whose version exactly
+matches the checkout's `package.json` version. Do not use `latest` or copy files
+from another REA version; the loader verifies the manifest version, ABI,
+architecture, and addon digest before it grants authority.
+
+From the checkout root, replace `<matching-version>` with the `version` in
+`package.json`:
+
+```sh
+npm pack rea-agents@<matching-version>
+tar -xzf rea-agents-<matching-version>.tgz
+mkdir -p native/windows/build
+cp package/native/windows/build/manifest.json native/windows/build/
+cp package/native/windows/build/rea-windows-x64.node native/windows/build/
+```
+
+This is a manual recovery step. REA does not fetch or install the artifact
+automatically. Alternatively, build it using the Linux/MinGW lane above.
+
 ## Boundaries
 
 - Opaque Node objects carry a native type tag, resource kind, and closed state.