Fix test image build: use amd64 runner, single-platform build

.github/workflows/docker-test.yml

@@ -12,7 +12,7 @@ permissions:
 
 jobs:
   build-test:
-    runs-on: ubuntu-24.04-arm
+    runs-on: ubuntu-24.04
     timeout-minutes: 30
 
     steps:
@@ -21,14 +21,11 @@ jobs:
       with:
         submodules: recursive
 
-    - name: Set up QEMU
-      uses: docker/setup-qemu-action@v3
-
     - name: Set up Docker Buildx
       uses: docker/setup-buildx-action@v3
 
     - name: Login to GitHub Container Registry
-      uses: docker/login-action@v3
+      uses: docker/login-action@v6
       with:
         registry: ghcr.io
         username: ${{ github.actor }}
@@ -39,7 +36,7 @@ jobs:
       with:
         context: .
         push: true
-        platforms: linux/amd64,linux/arm64
+        platforms: linux/amd64
         tags: ghcr.io/${{ github.repository }}:test
         cache-from: type=gha
         cache-to: type=gha,mode=max