fix: Add multi-platform Docker build support for ARM64

🔧 Added platforms: linux/amd64,linux/arm64 to Docker build to support:
- Intel/AMD x86_64 systems
- Apple Silicon M1/M2/M3 Macs (ARM64)
- ARM64 Linux servers

This fixes the 'no matching manifest for linux/arm64/v8' error when
pulling images on Apple Silicon Macs.

Also fixed missing space in IMAGE_NAME variable in attestation step.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

.github/workflows/build_and_publish_docker.yml

@@ -51,6 +51,7 @@ jobs:
       uses: docker/build-push-action@v5
       with:
         context: .
+        platforms: linux/amd64,linux/arm64
         push: true
         tags: ${{ steps.meta.outputs.tags }}
         labels: ${{ steps.meta.outputs.labels }}
@@ -60,7 +61,7 @@ jobs:
     - name: Generate artifact attestation
       uses: actions/attest-build-provenance@v1
       with:
-        subject-name: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME}}
+        subject-name: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
         subject-digest: ${{ steps.build.outputs.digest }}
         push-to-registry: true