docs: describe the per-arch Windows installers and CI artifacts

Author: EtienneLescot

technical-documentation/engineering/build-and-packaging.md

@@ -11,6 +11,7 @@ OpenScreen builds its renderer, Electron main process, preload bridge, native he
 | `npm run build` | Runs TypeScript checking, Vite, then unrestricted `electron-builder`. This is the full generic packaging command, but it does not proactively build platform helpers. **On Windows, prefer `build:win`** — see [Stale native artifacts](#stale-native-artifacts). |
 | `npm run build:mac` | Builds the ScreenCaptureKit and cursor helpers, checks TypeScript, runs Vite, and packages the macOS target. |
 | `npm run build:win` | Builds WGC/cursor helpers and the D3D11 compositor addon, fetches FFmpeg, checks TypeScript, runs Vite, and packages the Windows NSIS target without npm rebuild. |
+| `npm run build:win:arm64` | The same for Windows on ARM, into `electron/native/bin/win32-arm64/`. It has to run on an ARM64 host: the FFmpeg and ONNX Runtime fetches provision for the host. |
 | `npm run build:win:store` | Performs the Windows native and renderer build, then asks electron-builder for the configured AppX Store package. |
 | `npm run build:linux` | Checks TypeScript, runs Vite, then packages AppImage, Debian, pacman, and RPM artifacts without npm rebuild. Its explicit `--linux` target list overrides `linux.target` in `electron-builder.json5`, so a target added to the config alone is never built. |
 | `npm run build:native:mac` | Uses SwiftPM to build requested single-architecture ScreenCaptureKit and macOS cursor helpers and stages them under `electron/native/bin/darwin-*`. |
@@ -99,7 +100,7 @@ The fix is to link the CRT statically, which removes the dependency instead of o
 - CMake helpers — `set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>")` in `electron/native/wgc-capture/CMakeLists.txt`. These are standalone processes that share no CRT state with anything, so `/MT` costs about 100 KB each and nothing else.
 - Rust addon — `-C target-feature=+crt-static` in `crates/.cargo/config.toml`. Safe for the napi cdylib: only opaque `napi_value`s cross the boundary, and Buffers handed to Node carry a finalizer that frees, in the addon, what the addon allocated.
 
-`scripts/before-pack.cjs` reads the import table of every `.exe`/`.dll`/`.node` in `electron/native/bin/win32-x64/` and refuses to package a binary that needs a redistributable DLL **the package does not ship**. The `api-ms-win-crt-*` api-sets are deliberately not flagged: that is the UCRT, which does ship with Windows 10 and later.
+`scripts/before-pack.cjs` reads the import table of every `.exe`/`.dll`/`.node` in every shipped `electron/native/bin/win32-*/` folder and refuses to package a binary that needs a redistributable DLL **the package does not ship**, or one built for another architecture than its folder. The `api-ms-win-crt-*` api-sets are deliberately not flagged: that is the UCRT, which does ship with Windows 10 and later.
 
 #### `vcomp140.dll`: the member that got away
 
@@ -285,7 +286,7 @@ Copies of the same three files also remain at their old `public/` paths, because
 
 ### Windows
 
-The default electron-builder target is NSIS, with an assisted installer that allows users to change the installation directory. `npm run build:win:store` explicitly selects the configured `appx` target for Microsoft Store packaging. The AppX identity, publisher, capabilities, and Store languages come from `electron-builder.json5`. Release CI builds and retains both the NSIS installer and AppX package, although the GitHub release publisher currently downloads only the `openscreen-windows` NSIS artifact.
+The default electron-builder target is NSIS, with an assisted installer that allows users to change the installation directory. `npm run build:win:store` explicitly selects the configured `appx` target for Microsoft Store packaging. The AppX identity, publisher, capabilities, and Store languages come from `electron-builder.json5`. Release CI builds and retains both the NSIS installer and AppX package, although the GitHub release publisher currently downloads only the `openscreen-windows-x64` and `openscreen-windows-arm64` NSIS artifacts.
 
 #### Store tile assets
 

technical-documentation/engineering/ci-workflows.md

@@ -98,7 +98,7 @@ Jobs that need the root dependencies use `.github/actions/setup`, which requests
 
 A `v*` tag or manual dispatch starts platform builds. Dispatch accepts `arch` (`arm64`, `x64`, or `both`) for macOS and an optional `release_tag` that enables publication.
 
-- `build-windows` runs `npm run build:win` and uploads `openscreen-windows` for 30 days.
+- `build-windows` is an `x64`/`arm64` matrix, each on a runner of its own arch (`windows-latest`, `windows-11-arm`). It runs `npm run build:win` or `npm run build:win:arm64` and uploads `openscreen-windows-x64` or `openscreen-windows-arm64` for 30 days, with a JSON sidecar that `publish-release` folds into one `latest.yml` listing both installers.
 - `build-windows-store` runs `npm run build:win:store` and uploads `openscreen-windows-store` for 30 days.
 - `build-macos` is an `arm64`/`x64` matrix. It builds Vite/Electron and native helpers, packages and optionally signs the app, creates DMGs, notarizes every signed build including pre-releases, and uploads one artifact per architecture for 30 days.
 - `build-linux` produces AppImage, deb, pacman, and rpm files and uploads `openscreen-linux` for 30 days. It asserts one artifact per format before uploading, because `if-no-files-found: error` evaluates the union of the upload globs and so cannot catch a single format that stopped being produced. No zsync: it was electron-updater's older AppImage delta format, and app-builder-lib 26.x embeds a block map in the AppImage instead — which is what the in-app updater (`electron/auto-updater.ts`) reads for a differential download.

technical-documentation/testing/manual-e2e-checklist.md

@@ -49,12 +49,12 @@ A release candidate is tested on what CI built, not on a dev build. The artifact
 
 ```bash
 gh run list -R getopenscreen/openscreen --workflow build.yml --branch <branch>
-gh run download <run-id> -R getopenscreen/openscreen -n openscreen-windows
+gh run download <run-id> -R getopenscreen/openscreen -n openscreen-windows-x64
 ```
 
 | Artifact | What it holds |
 |---|---|
-| `openscreen-windows` | `Openscreen.Setup.<version>.exe`, the NSIS installer, with its `.blockmap` and `latest.yml` |
+| `openscreen-windows-x64`, `openscreen-windows-arm64` | `Openscreen.Setup.<version>-x64.exe` or `Openscreen.Setup.<version>-arm64.exe`, the NSIS installer, with its `.blockmap` and the update-feed JSON |
 | `openscreen-windows-store` | `Openscreen.Setup.<version>.appx`, the Store package |
 | `openscreen-mac-arm64`, `openscreen-mac-x64` | `Openscreen-macOS-Apple-Silicon-<version>.dmg` or `Openscreen-macOS-Intel-<version>.dmg`, with the update ZIP and its JSON |
 | `openscreen-linux` | `Openscreen-Linux-<version>` as `.AppImage`, `.deb`, `.rpm` and `.pacman`, with `latest-linux.yml` |