Windows arm64 desktop installer (1.18.31) never places OpenCode.exe; x64 is fine

Summary

opencode-desktop-win-arm64.exe from v1.18.31 completes successfully, extracts the full Electron payload, registers itself under Uninstall, and writes Start Menu and Desktop shortcuts, but never places OpenCode.exe. The app cannot be launched, and the installer's own shortcut points at a file that does not exist.

The x64 asset from the same release is unaffected, so this looks specific to the arm64 packaging.

Reproduction

Windows 11 arm64, build 26200.9168 (25H2), standard non-admin user.

# Asset from the v1.18.31 release, 118,867,704 bytes
# Authenticode: Valid
#   CN="Anomaly Innovations, Inc https://anoma.ly/", O=..., L=Dover, S=Delaware, C=US
Start-Process -FilePath .\opencode-desktop-win-arm64.exe -ArgumentList "/S" -Wait -PassThru   # exit 0

Test-Path "$env:LOCALAPPDATA\Programs\@opencode-aidesktop\OpenCode.exe"
# False

What is on disk afterwards

Install directory %LOCALAPPDATA%\Programs\@opencode-aidesktop, 225.5 MB total:

locales/
resources/                  (app.asar present)
chrome_100_percent.pak
chrome_200_percent.pak
icudtl.dat
LICENSE.electron.txt
LICENSES.chromium.html
resources.pak
snapshot_blob.bin
Uninstall OpenCode.exe
v8_context_snapshot.bin
vk_swiftshader_icd.json

The only .exe files anywhere under the install root are Uninstall OpenCode.exe, resources\elevate.exe, and a bundled OpenConsole.exe. There is no application binary.

The registered uninstall entry is OpenCode 1.18.31, with:

• DisplayIcon = C:\Users\<user>\AppData\Local\Programs\@opencode-aidesktop\OpenCode.exe,0 which does not exist
• no InstallLocation value at all

The vendor-created shortcut OpenCode.lnk targets that same missing path.

Ruling out the obvious causes

• Not silent-mode specific. Uninstalling and running the installer interactively by double-click produces the same result. Payload directories are rewritten, OpenCode.exe still absent.
• Not antivirus. Reinstalling while polling the target path every 400 ms shows the file never appears at any point, so nothing removed it after the fact. Get-MpThreatDetection and Get-MpThreat are empty.
• Not x64. opencode-desktop-win-x64.exe from the same release, installed with the same /S flag on a windows-latest x64 runner, exits 0 and produces ...\Programs\@opencode-aidesktop\OpenCode.exe as expected.

Possibly related packaging detail

The arm64 build ships x64 native prebuilds:

resources\app.asar.unpacked\node_modules\@lydell\node-pty-win32-x64\prebuilds\win32-x64\conpty\OpenConsole.exe

That may be unrelated to the missing binary, but it suggests the arm64 target's file selection is not doing what is intended.

Expected

The arm64 installer places OpenCode.exe in the install directory, matching what DisplayIcon and the generated shortcuts already point at.