Optimize CI workflow configuration

- Remove strategy matrix from CI workflow
- Set CI runs-on to ubuntu-latest for simplicity

.github/workflows/ci.yaml

@@ -12,11 +12,7 @@ concurrency:
   cancel-in-progress: true
 jobs:
   build-test:
-    strategy:
-      fail-fast: false
-      matrix:
-        os: [macos-latest, ubuntu-latest]
-    runs-on: ${{matrix.os}}
+    runs-on: ubuntu-latest
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4