fork: add Windows test build workflow (DO NOT UPSTREAM)

Fork-only workflow producing unsigned Windows installers + updater metadata
as GitHub releases on StiensWout/t3code, for install/in-app-update/WSL
verification of the server.asar sidecar packaging. Drop this commit before
opening the upstream PR.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
cc7c34ce3cWout Stiens committed on 8/10/2026, 1:59:02 PMparent1e2eba3
1 file changedLine totals unavailable