feat(ci): use native runners for cross-platform testing via artifact transfer

Cross-compile on pixi-supported platforms, upload binaries, then run tests
on native runners (macos-15-intel, ubuntu-24.04-arm) instead of QEMU/Rosetta.
Add test-run pixi environment for lightweight test-only platform support.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: 16bit-ykiko

.github/workflows/test-cmake.yml

@@ -29,13 +29,16 @@ jobs:
             build_type: Debug
           - os: macos-15
             build_type: RelWithDebInfo
-          # ── Additional platform builds ─────────────────────────────────
+          # ── Cross-compile (build only, tests run on native runners) ────
           - os: macos-15
             build_type: RelWithDebInfo
             target_triple: x86_64-apple-darwin
+            build_only: true
           - os: ubuntu-24.04
             build_type: RelWithDebInfo
             target_triple: aarch64-linux-gnu
+            build_only: true
+          # ── Native ARM64 build + test ─────────────────────────────────
           - os: windows-11-arm
             build_type: RelWithDebInfo
             target_triple: aarch64-pc-windows-msvc
@@ -64,13 +67,6 @@ jobs:
           fi
         shell: bash
 
-      - name: Setup QEMU for aarch64 tests
-        if: matrix.target_triple == 'aarch64-linux-gnu'
-        run: |
-          sudo apt-get update
-          sudo apt-get install -y qemu-user-static libc6-arm64-cross libstdc++6-arm64-cross
-          echo "QEMU_LD_PREFIX=/usr/aarch64-linux-gnu" >> "$GITHUB_ENV"
-
       - name: Build (native)
         if: ${{ !matrix.target_triple }}
         run: pixi run build ${{ matrix.build_type }} ON
@@ -79,17 +75,28 @@ jobs:
         if: ${{ matrix.target_triple }}
         shell: bash
         run: |
-          pixi run cmake-config ${{ matrix.build_type }} OFF "-DCLICE_ENABLE_TEST=ON -DCLICE_TARGET_TRIPLE=${{ matrix.target_triple }}"
+          pixi run cmake-config ${{ matrix.build_type }} OFF "-DCLICE_TARGET_TRIPLE=${{ matrix.target_triple }}"
           pixi run cmake-build ${{ matrix.build_type }}
 
+      - name: Upload cross-compiled binaries
+        if: ${{ matrix.build_only }}
+        uses: actions/upload-artifact@v4
+        with:
+          name: cross-build-${{ matrix.target_triple }}
+          path: build/${{ matrix.build_type }}/bin/
+          if-no-files-found: error
+          retention-days: 1
+
       - name: Unit Test
+        if: ${{ !matrix.build_only }}
         run: pixi run unit-test ${{ matrix.build_type }}
 
       - name: Integration Test
+        if: ${{ !matrix.build_only }}
         run: pixi run integration-test ${{ matrix.build_type }}
 
       - name: Smoke Test
-        if: success() || failure()
+        if: ${{ !matrix.build_only && (success() || failure()) }}
         run: pixi run smoke-test ${{ matrix.build_type }}
 
       - name: Print cache stats and stop server
@@ -102,3 +109,43 @@ jobs:
             pixi run -- ccache --show-stats
           fi
         shell: bash
+
+  test-cross:
+    needs: build
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - os: macos-15-intel
+            build_type: RelWithDebInfo
+            target_triple: x86_64-apple-darwin
+          - os: ubuntu-24.04-arm
+            build_type: RelWithDebInfo
+            target_triple: aarch64-linux-gnu
+    runs-on: ${{ matrix.os }}
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - uses: ./.github/actions/setup-pixi
+        with:
+          environments: test-run
+
+      - name: Download cross-compiled binaries
+        uses: actions/download-artifact@v4
+        with:
+          name: cross-build-${{ matrix.target_triple }}
+          path: build/${{ matrix.build_type }}/bin/
+
+      - name: Make binaries executable
+        run: chmod +x build/${{ matrix.build_type }}/bin/*
+
+      - name: Unit Test
+        run: pixi run -e test-run unit-test ${{ matrix.build_type }}
+
+      - name: Integration Test
+        run: pixi run -e test-run integration-test ${{ matrix.build_type }}
+
+      - name: Smoke Test
+        if: success() || failure()
+        run: pixi run -e test-run smoke-test ${{ matrix.build_type }}