shard host tests

Author: habdelra

Diff for: .github/workflows/ci.yaml

@@ -148,6 +148,11 @@ jobs:
     concurrency:
       group: boxel-host-test${{ github.head_ref || github.run_id }}
       cancel-in-progress: true
+    strategy:
+      fail-fast: false
+      matrix:
+        shardIndex: [1, 2, 3]
+        shardTotal: [3]
     steps:
       - uses: actions/checkout@v4
       - uses: ./.github/actions/init