ci(build): run linux/arm64 on native runner, drop QEMU

The multi-arch build emulated arm64 via QEMU, whose user-mode emulation segfaulted
glibc ldconfig during the libc-bin trigger ("qemu: uncaught target signal 11"),
deterministically failing the arm64 leg. Pair each linux arch with a native runner via
a matrix include (amd64 -> ubuntu-latest, arm64 -> ubuntu-24.04-arm), set runs-on to
${{ matrix.runner }}, and drop the Set up QEMU step. Native runners build each arch with
no emulation, so the segfault can't occur and builds are faster. ubuntu-24.04-arm is GA
and free for public repos.

Signed-off-by: benshi <807629978@qq.com>
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: BenLocal

.github/workflows/build.yml

@@ -28,12 +28,19 @@ jobs:
       matrix:
         platform: [linux/amd64, linux/arm64]
         branch: [master, feature/transcode2]
-    runs-on: ubuntu-latest
+        # Build each arch on a native runner so docker buildx never emulates:
+        # foreign-arch QEMU segfaults glibc ldconfig (libc-bin trigger -> "qemu:
+        # uncaught target signal 11"), which broke the arm64 leg. ubuntu-24.04-arm
+        # is GA and free for public repos.
+        include:
+          - platform: linux/amd64
+            runner: ubuntu-latest
+          - platform: linux/arm64
+            runner: ubuntu-24.04-arm
+    runs-on: ${{ matrix.runner }}
     steps:
       - name: Checkout
         uses: actions/checkout@v5
-      - name: Set up QEMU
-        uses: docker/setup-qemu-action@v3
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
       - name: prepare