fix(ci): add QEMU for arm64 apt-get in Docker build

Plain docker build --platform linux/arm64 on amd64 runner needs QEMU
to execute RUN commands. QEMU is only needed for apt-get (seconds),
not for Rust compilation (the binaries are pre-built).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.github/workflows/release.yml

@@ -102,6 +102,10 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      - uses: docker/setup-qemu-action@v3
+        with:
+          platforms: arm64
+
       - uses: docker/setup-buildx-action@v3
 
       - uses: docker/login-action@v3