CI: ship jfjoch_viewer to release as a Linux-agnostic .tgz

Add a build-viewer-tgz job on the oldest runner (RHEL 8) that builds
JFJOCH_VIEWER_ONLY with cuda12.9 and nocuda and uploads a self-contained
jfjoch_viewer-<version>-linux-{cuda<major>|cpu}.tgz to the release, mirroring
the Windows installer naming. CMake gains a Linux viewer-only CPack path that
emits a single TGZ instead of an RPM/DEB. Drop the per-distro viewer RPM/DEB
from the release uploads (writer + XDS plugin still go there); the viewer
packages continue to publish to the package repositories unchanged.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

.gitea/workflows/build_and_test.yml

@@ -110,6 +110,52 @@ jobs:
             python gitea_upload_file.py $file.FullName
             if ($LASTEXITCODE -ne 0) { throw "Upload failed for $($file.Name)" }
           }
+  build-viewer-tgz:
+    name: build:viewer-tgz:${{ matrix.variant }}
+    runs-on: jfjoch_rocky8
+    timeout-minutes: 120
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - variant: cuda
+            use_cuda: 'ON'
+          - variant: cpu
+            use_cuda: 'OFF'
+    steps:
+      - uses: actions/checkout@v4
+      - name: Configure viewer build
+        shell: bash
+        run: |
+          mkdir -p build
+          cd build
+          cmake -G Ninja -DJFJOCH_VIEWER_ONLY=ON -DJFJOCH_USE_CUDA=${{ matrix.use_cuda }} ${{ env.MARCH_CMAKE_FLAGS }} -DCMAKE_BUILD_TYPE=Release ..
+      - name: Build viewer tgz
+        shell: bash
+        run: |
+          cd build
+          ninja -j16 jfjoch_viewer
+          cpack
+      - name: Upload viewer tgz to release
+        if: github.ref_type == 'tag'
+        shell: bash
+        env:
+          TOKEN: ${{ secrets.PIP_REPOSITORY_API_TOKEN }}
+        run: |
+          set -euo pipefail
+          shopt -s nullglob
+          # CMakeLists.txt names the archive jfjoch_viewer-<version>-linux-{cuda<major>|cpu}.tar.gz;
+          # rename to .tgz (matching the Windows installer's release naming) before upload.
+          files=(build/jfjoch_viewer-*.tar.gz)
+          if [ ${#files[@]} -eq 0 ]; then
+            echo "No viewer archive found in build/"
+            exit 1
+          fi
+          for file in "${files[@]}"; do
+            tgz="${file%.tar.gz}.tgz"
+            mv "$file" "$tgz"
+            python3 gitea_upload_file.py "$tgz"
+          done
   build-rpm:
     name: build:rpm (${{ matrix.distro }})
     if: github.ref_type != 'workflow_dispatch'
@@ -207,16 +253,19 @@ jobs:
           
           cd ..
           
+          # The viewer is shipped to the release as a Linux-version-agnostic .tgz by the
+          # build-viewer-tgz job; only the writer (and the XDS plugin .so on rocky8) go to the
+          # release as distro packages here.
           if [ "${{ matrix.distro }}" = "rocky8_nocuda" ]; then
-            for file in build/jfjoch-viewer*.rpm build/jfjoch-writer*rpm build/xds-plugin/libjfjoch_xds_plugin.so.*; do
+            for file in build/jfjoch-writer*rpm build/xds-plugin/libjfjoch_xds_plugin.so.*; do
                  python3 gitea_upload_file.py "$file"
             done
           elif [ "${{ matrix.distro }}" = "rocky9_nocuda" ]; then
-            for file in build/jfjoch-viewer*.rpm build/jfjoch-writer*rpm; do
+            for file in build/jfjoch-writer*rpm; do
                  python3 gitea_upload_file.py "$file"
             done
           elif [ "${{ matrix.distro }}" = "ubuntu2204_nocuda" ]; then
-            for file in build/jfjoch*viewer*.deb build/jfjoch*writer*.deb; do
+            for file in build/jfjoch*writer*.deb; do
                  python3 gitea_upload_file.py "$file"
             done
           fi

CMakeLists.txt

@@ -406,6 +406,19 @@ elseif (WIN32)
     # backslash there ("bin\jfjoch...") is an invalid escape that cmake 4.x (CMP0010 strict, e.g. the
     # VS-bundled cmake) rejects when cpack re-parses it. Windows accepts the forward slash at runtime.
     set(CPACK_NSIS_INSTALLED_ICON_NAME "bin/jfjoch_viewer.exe")
+elseif (JFJOCH_VIEWER_ONLY)
+    # Linux portable viewer: a single self-contained .tar.gz of jfjoch_viewer (Qt is linked
+    # statically here, so there is nothing external to ship alongside the binary). Built on the
+    # oldest supported distro (RHEL 8) for a low glibc floor, so the archive runs on any newer
+    # Linux -- unlike the per-distro .rpm/.deb this is meant to replace in the release. Named to
+    # mirror the Windows/macOS artifacts, with the same -cuda<major>/-cpu tag so the (larger) GPU
+    # build is self-identifying. CI renames the .tar.gz to .tgz before upload.
+    set(CPACK_GENERATOR "TGZ")
+    if (JFJOCH_CUDA_AVAILABLE)
+        set(CPACK_PACKAGE_FILE_NAME "jfjoch_viewer-${JFJOCH_VERSION}-linux-cuda${CUDAToolkit_VERSION_MAJOR}")
+    else()
+        set(CPACK_PACKAGE_FILE_NAME "jfjoch_viewer-${JFJOCH_VERSION}-linux-cpu")
+    endif()
 elseif (EXISTS "/etc/debian_version")
     set(CPACK_PACKAGE_LICENSE "GPL-3.0-only")
     set(CPACK_RESOURCE_FILE_LICENSE "${CMAKE_SOURCE_DIR}/LICENSE")