👷 add ensure-compatibility job to compare Swift outputs with qs.js

Author: techouse

.github/workflows/test.yml

@@ -248,3 +248,42 @@ jobs:
           name: macOS-crashlogs-objc-xcode-${{ matrix.xcode }}-${{ matrix.os }}
           path: crashlogs-objc
           if-no-files-found: ignore
+
+  ensure-compatibility:
+    name: Ensure compatibility with qs.js
+    needs: analyze
+    runs-on: macos-15
+    timeout-minutes: 15
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+        with:
+          fetch-depth: 0
+
+      - name: Select Xcode
+        uses: maxim-lobanov/setup-xcode@v1
+        with:
+          xcode-version: '16.3'
+
+      - name: Show Xcode & Swift versions
+        run: |
+          xcodebuild -version
+          swift --version
+
+      - name: Install Node.js 20
+        uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+
+      - name: Install qs.js
+        working-directory: Tools/QsSwiftComparison
+        run: npm install
+
+      - name: Compare Swift vs qs.js outputs (deterministic)
+        if: ${{ always() }}
+        continue-on-error: true
+        working-directory: Tools/QsSwiftComparison
+        env:
+          SWIFT_DETERMINISTIC_HASHING: 1
+          LC_ALL: C
+        run: bash compare_outputs.sh