chore: remove setup-qemu-action from build workflows

QEMU is unnecessary since all platform builds run on native runners.

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

Author: gugu

.github/workflows/build-agent.yml

@@ -67,9 +67,6 @@ jobs:
           name: bake-meta
           path: /tmp
 
-      - name: Set up QEMU
-        uses: docker/setup-qemu-action@v3
-
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
 

.github/workflows/build.yml

@@ -68,9 +68,6 @@ jobs:
           name: bake-meta
           path: /tmp
 
-      - name: Set up QEMU
-        uses: docker/setup-qemu-action@v3
-
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3