CI: drive the Windows rugnux build from cmd, as the viewer build already does

The job used shell: bash, and the Windows runner has no bash on PATH, so it
failed before running cmake. It also skipped the MSVC environment, which every
cmake invocation on that runner needs: build-windows calls vcvars64.bat, located
through vswhere, at the start of each step. Follow it exactly - cmd, the same
vcvars preamble, -G Ninja, and cpack from inside the build directory - and keep
powershell only for the upload, which is what build-windows uses there too.

CMAKE_PREFIX_PATH drops the Qt entry and keeps C:/deps: JFJOCH_RUGNUX_ONLY is
the portable subtree minus viewer/, so it needs Eigen and ZLIB and no Qt.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SQjneRUssfhi1k9rq8Ts3h

.gitea/workflows/build_and_test.yml

@@ -239,17 +239,32 @@ jobs:
   build-rugnux-windows:
     name: build:rugnux:windows
     runs-on: windows-11-cuda-qt
+    timeout-minutes: 120
     steps:
       - uses: actions/checkout@v4
+      # cmd, not bash: the Windows runner has no bash, and every cmake invocation needs the MSVC
+      # environment from vcvars64.bat first -- same shape as build-windows above. No Qt in
+      # CMAKE_PREFIX_PATH: JFJOCH_RUGNUX_ONLY is the portable subtree minus viewer/, so C:/deps
+      # (Eigen, ZLIB) is all it needs.
       - name: Configure rugnux build
-        shell: bash
-        # No Qt needed: JFJOCH_RUGNUX_ONLY is the portable subtree minus viewer/.
+        shell: cmd
         run: |
-          cmake -S . -B build-rugnux -DJFJOCH_RUGNUX_ONLY=ON -DJFJOCH_USE_CUDA=ON \
-            ${{ env.MSVC_ARCH_CMAKE_FLAGS }} -DCMAKE_BUILD_TYPE=Release
+          for /f "usebackq tokens=*" %%i in (`"%ProgramFiles(x86)%\Microsoft Visual Studio\Installer\vswhere.exe" -latest -property installationPath`) do set "VSPATH=%%i"
+          call "%VSPATH%\VC\Auxiliary\Build\vcvars64.bat"
+          cmake -G Ninja -B build-rugnux -DJFJOCH_RUGNUX_ONLY=ON -DJFJOCH_USE_CUDA=ON -DCMAKE_BUILD_TYPE=Release ${{ env.MSVC_ARCH_CMAKE_FLAGS }} -DCMAKE_PREFIX_PATH="C:/deps"
+      - name: Build rugnux
+        shell: cmd
+        run: |
+          for /f "usebackq tokens=*" %%i in (`"%ProgramFiles(x86)%\Microsoft Visual Studio\Installer\vswhere.exe" -latest -property installationPath`) do set "VSPATH=%%i"
+          call "%VSPATH%\VC\Auxiliary\Build\vcvars64.bat"
+          cmake --build build-rugnux
       - name: Build rugnux zip
-        shell: bash
-        run: cmake --build build-rugnux --config Release --target PACKAGE -j
+        shell: cmd
+        run: |
+          for /f "usebackq tokens=*" %%i in (`"%ProgramFiles(x86)%\Microsoft Visual Studio\Installer\vswhere.exe" -latest -property installationPath`) do set "VSPATH=%%i"
+          call "%VSPATH%\VC\Auxiliary\Build\vcvars64.bat"
+          cd build-rugnux
+          cpack
       - name: Upload rugnux zip to release
         if: github.ref_type == 'tag'
         shell: powershell