Fix macOS ARM CI: bust stale x86_64 CEF cache, add arch check

Bump cache key to v2 to force re-download of the correct arm64 CEF
binary (a previous run cached x86_64 artifacts before platform
detection was fixed, causing link failures).

Add a "Verify CEF architecture" step that runs lipo -info on
libcef_dll_wrapper.a and fails fast if arm64 is not present.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: linesight

.github/workflows/ci-macos.yml

@@ -48,7 +48,7 @@ jobs:
           path: |
             build/cef_binary_*
             build/cef*_macarm64
-          key: cef-macosarm64-${{ steps.cef-version.outputs.value }}
+          key: cef-macosarm64-v2-${{ steps.cef-version.outputs.value }}
 
       - name: Install build tools
         run: python tools/requirements.py
@@ -59,6 +59,14 @@ jobs:
       - name: Prepare prebuilt CEF
         run: python tools/automate.py --prebuilt-cef
 
+      - name: Verify CEF architecture
+        run: |
+          wrapper=$(ls build/cef*_macarm64/lib/libcef_dll_wrapper.a 2>/dev/null | head -1)
+          if [ -z "$wrapper" ]; then echo "libcef_dll_wrapper.a not found"; exit 1; fi
+          archs=$(lipo -info "$wrapper" 2>&1)
+          echo "$archs"
+          echo "$archs" | grep -q arm64 || (echo "ERROR: libcef_dll_wrapper.a is not arm64"; exit 1)
+
       - name: Configure CMake
         run: cmake -S . -B build/_cmake_build -G Ninja -DCMAKE_BUILD_TYPE=Release