ci: add Raspberry Pi OS ARM testing (32-bit and 64-bit)

Add QEMU-based ARM testing for both armhf (32-bit) and arm64 (64-bit)
architectures to validate installer on Raspberry Pi OS Lite. Tests run
only on PRs to main branch to conserve CI resources while ensuring
compatibility with ARM platforms before merge.

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

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

.github/workflows/test.yml

@@ -164,3 +164,63 @@ jobs:
         echo "✓ Pip packages: bleak, bluezero" >> $GITHUB_STEP_SUMMARY
         echo "✓ Install method: System packages (no compilation)" >> $GITHUB_STEP_SUMMARY
         echo "✓ Installation time: < 1 minute" >> $GITHUB_STEP_SUMMARY
+
+  installer-test-arm:
+    name: Installer Test (Raspberry Pi OS - ARM)
+    runs-on: ubuntu-latest
+    # Only run on pull requests to main branch
+    if: github.event_name == 'pull_request' && github.base_ref == 'main'
+    timeout-minutes: 20  # ARM emulation is slower, allow extra time
+
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          # Raspberry Pi OS 32-bit (armhf/armv7)
+          # Based on Debian Bookworm - matches Raspberry Pi OS Lite 32-bit
+          - os-image: "arm32v7/debian:bookworm"
+            platform: "linux/arm/v7"
+            arch-name: "Raspberry Pi OS 32-bit (armhf)"
+
+          # Raspberry Pi OS 64-bit (arm64/aarch64)
+          # Based on Debian Bookworm - matches Raspberry Pi OS Lite 64-bit
+          - os-image: "arm64v8/debian:bookworm"
+            platform: "linux/arm64"
+            arch-name: "Raspberry Pi OS 64-bit (arm64)"
+
+    steps:
+    - name: Checkout code
+      uses: actions/checkout@v4
+
+    - name: Set up QEMU
+      uses: docker/setup-qemu-action@v3
+      with:
+        platforms: arm,arm64
+
+    - name: Run installer test on ${{ matrix.arch-name }}
+      run: |
+        docker run --rm \
+          --platform ${{ matrix.platform }} \
+          -v $PWD:/workspace \
+          -w /workspace \
+          -e DEBIAN_FRONTEND=noninteractive \
+          -e DEBCONF_NONINTERACTIVE_SEEN=true \
+          -e TZ=UTC \
+          ${{ matrix.os-image }} \
+          bash tests/test_installer.sh
+      continue-on-error: false
+
+    - name: Installation summary
+      if: always()
+      run: |
+        echo "## ARM Installer Test Results" >> $GITHUB_STEP_SUMMARY
+        echo "**Architecture:** ${{ matrix.arch-name }}" >> $GITHUB_STEP_SUMMARY
+        echo "**Platform:** ${{ matrix.platform }}" >> $GITHUB_STEP_SUMMARY
+        echo "**Base Image:** ${{ matrix.os-image }}" >> $GITHUB_STEP_SUMMARY
+        echo "" >> $GITHUB_STEP_SUMMARY
+        echo "✓ System packages: python3-gi, python3-dbus, python3-cairo, bluez" >> $GITHUB_STEP_SUMMARY
+        echo "✓ Pip packages: bleak==1.1.1, bluezero" >> $GITHUB_STEP_SUMMARY
+        echo "✓ BLE interface files copied" >> $GITHUB_STEP_SUMMARY
+        echo "✓ BlueZ experimental mode configured" >> $GITHUB_STEP_SUMMARY
+        echo "" >> $GITHUB_STEP_SUMMARY
+        echo "_Note: Tests run via QEMU emulation (2-5x slower than native)_" >> $GITHUB_STEP_SUMMARY