CI: add macOS nightly wheels for free-threaded CPython

Also bump the regular aarch64 wheel builds to `musllinux_1_2`;
that's an inconsistency in config with numpy that is addressed here
(noted because the Linux free-threaded wheels made that bump too).

.github/workflows/freethreaded_wheels.yml

@@ -44,7 +44,8 @@ jobs:
         name: Install Python
         with:
           python-version: "3.10"
-      - name: Setup environment variables
+
+      - name: Install build deps; set CIBW environment variables
         run: |
           PYPI_URL="https://pypi.anaconda.org/scientific-python-nightly-wheels/simple"
           CIBW_DEPS="pip install --upgrade pip build &&\
@@ -72,9 +73,78 @@ jobs:
           path: ./dist/*.whl
           if-no-files-found: error
 
+  build_macos_free_threaded_wheels:
+    name: Build ${{ matrix.cibw_python }} ${{ matrix.cibw_arch }} ${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        # macos-13 is the last runner that supports Intel (x86_64) architecture
+        os: [macos-13, macos-14]
+        cibw_python: ["cp313t"]
+        cibw_arch: ["x86_64", "arm64"]
+        exclude:
+          - os: macos-14
+            cibw_arch: "x86_64"
+          - os: macos-13
+            cibw_arch: "arm64"
+    steps:
+      - uses: actions/checkout@9bb56186c3b09b4f86b1c65136769dd318469633 # v4.1.2
+        with:
+          fetch-depth: 0
+
+      - uses: actions/setup-python@v5
+        name: Install Python
+        with:
+          python-version: "3.12"
+
+      - name: Install build deps; set CIBW environment variables
+        run: |
+          PYPI_URL="https://pypi.anaconda.org/scientific-python-nightly-wheels/simple"
+          CIBW_DEPS="pip install --upgrade pip build &&\
+                     pip install --pre -i $PYPI_URL cython numpy scipy &&\
+                     pip install pytest meson-python ninja"
+          echo "CIBW_BEFORE_BUILD=$CIBW_DEPS" >> "$GITHUB_ENV"
+          echo "CIBW_BEFORE_TEST=$CIBW_DEPS" >> "$GITHUB_ENV"
+          echo "CIBW_TEST_COMMAND=PYTHON_GIL=0 $CIBW_TEST_COMMAND" >> "$GITHUB_ENV"
+
+      - name: Build wheels for CPython (macOS) (x86_64)
+        if: matrix.cibw_arch == 'x86_64'
+        uses: pypa/cibuildwheel@a8d190a111314a07eb5116036c4b3fb26a4e3162 # v2.19.0
+        with:
+          output-dir: dist
+        env:
+          CIBW_BUILD: ${{ matrix.cibw_python }}-*
+          CIBW_ARCHS_MACOS: ${{ matrix.cibw_arch }}
+          CIBW_PRERELEASE_PYTHONS: True
+          CIBW_FREE_THREADED_SUPPORT: True
+          CIBW_BUILD_FRONTEND: "pip; args: --no-build-isolation"
+
+      - name: Build wheels for CPython (macOS) (arm64)
+        if: matrix.cibw_arch == 'arm64'
+        uses: pypa/cibuildwheel@a8d190a111314a07eb5116036c4b3fb26a4e3162 # v2.19.0
+        with:
+          output-dir: dist
+        env:
+          CIBW_BUILD: ${{ matrix.cibw_python }}-*
+          CIBW_ARCHS_MACOS: ${{ matrix.cibw_arch }}
+          CIBW_PRERELEASE_PYTHONS: True
+          CIBW_FREE_THREADED_SUPPORT: True
+          CIBW_BUILD_FRONTEND: "pip; args: --no-build-isolation"
+
+      - uses: actions/upload-artifact@65462800fd760344b1a7b4382951275a0abb4808 # v4.3.3
+        with:
+          name: wheels_macos_${{ matrix.cibw_arch }}_${{ matrix.cibw_python }}
+          path: ./dist/*.whl
+          if-no-files-found: error
+
   deploy_anaconda:
     name: Release (Anaconda)
-    needs: [build_linux_x86_64_free_threaded_wheels]
+    needs:
+      [
+        build_linux_x86_64_free_threaded_wheels,
+        build_macos_free_threaded_wheels,
+      ]
     # Run only on pushes to the main branch, on schedule, or when triggered manually
     if: >-
       github.repository == 'PyWavelets/pywt' &&