ci: temporary Windows desktop artifact build for #533 testing (no release)

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.github/workflows/desktop-win-artifact.yml

@@ -0,0 +1,47 @@
+name: Desktop Windows Artifact (test)
+
+# Temporary, no-release build of the Windows desktop installer for manual
+# testing of the run_jarvis_command backend-spawn fix (#531/PR #533). Builds
+# on windows-latest and uploads the NSIS .exe as a workflow artifact — it does
+# NOT touch the shared desktop-edge release channel.
+
+on:
+  push:
+    branches:
+      - 'ci/windows-desktop-artifact'
+  workflow_dispatch:
+
+jobs:
+  build-windows:
+    runs-on: windows-latest
+    steps:
+      - uses: actions/checkout@v6
+
+      - name: Install Rust stable
+        uses: dtolnay/rust-toolchain@stable
+
+      - name: Rust cache
+        uses: swatinem/rust-cache@v2
+        with:
+          workspaces: 'frontend/src-tauri -> target'
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v6
+        with:
+          node-version: '22'
+
+      - name: Install frontend dependencies
+        working-directory: frontend
+        run: npm install
+
+      - name: Build Tauri (Windows NSIS, no publish, no updater signing)
+        working-directory: frontend
+        shell: bash
+        run: npx tauri build --bundles nsis --config '{"bundle":{"createUpdaterArtifacts":false}}'
+
+      - name: Upload Windows installer
+        uses: actions/upload-artifact@v4
+        with:
+          name: openjarvis-windows-setup
+          path: frontend/src-tauri/target/release/bundle/nsis/*.exe
+          if-no-files-found: error