ci: switch riscv64 from QEMU to native RISE runner (#117)

* ci: switch riscv64 from QEMU to native RISE runner

* fix: use RISE runner Python, skip setup-uv on riscv64

* fix: run cibuildwheel via pipx on riscv64 (bypass setup-python)

.github/workflows/wheels.yml

@@ -26,7 +26,7 @@ jobs:
           - os: windows-2022
           - os: windows-11-arm
           - os: macOS-14
-          - os: ubuntu-22.04
+          - os: ubuntu-24.04-riscv
             cibw_archs: "riscv64"
             name_suffix: "-riscv64"
 
@@ -39,20 +39,28 @@ jobs:
           persist-credentials: false
 
       - uses: astral-sh/setup-uv@37802adc94f370d6bfd71619e3f0bf239e1f3b78 # v7.6.0
+        if: matrix.cibw_archs != 'riscv64'
         with:
           enable-cache: false
 
-      - name: Set up QEMU for RISC-V emulation
-        if: matrix.cibw_archs == 'riscv64'
-        uses: docker/setup-qemu-action@ce360397dd3f832beb865e1373c09c0e9f86d70a # v4.0.0
-        with:
-          platforms: riscv64
-
-      # See pyproject.toml for config.
+      # Use the GitHub Action for all platforms except riscv64
       - uses: pypa/cibuildwheel@ee02a1537ce3071a004a6b08c41e72f0fdc42d9a # v3.4.0
+        if: matrix.cibw_archs != 'riscv64'
         env:
           CIBW_ARCHS: ${{ matrix.cibw_archs || 'auto' }}
 
+      # On riscv64 native runners, run cibuildwheel via pipx to avoid
+      # the GitHub Action's setup-python call (not available for riscv64)
+      - name: Build wheels (riscv64 native)
+        if: matrix.cibw_archs == 'riscv64'
+        run: |
+          export PATH="$(ls -d /opt/python-3.1*/bin 2>/dev/null | sort -V | tail -1):$PATH"
+          python3 --version
+          python3 -m pip install pipx
+          pipx run cibuildwheel --output-dir wheelhouse
+        env:
+          CIBW_ARCHS: riscv64
+
       - uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f # v7.0.0
         with:
           name: wheels-${{ matrix.os }}${{ matrix.name_suffix || '' }}-${{ strategy.job-index }}