Add local and CI quality gates

.github/workflows/python-tests.yml

@@ -41,21 +41,35 @@ jobs:
         with:
           python-version: "3.12"
 
+      - name: Set up Node.js
+        uses: actions/setup-node@53b83947a5a98c8d113130e565377fae1a50d02f # v6.3.0
+        with:
+          node-version: "20"
+          cache: "npm"
+
       - name: Install quality tools
         run: |
           python -m pip install --upgrade pip
           pip install -r requirements.txt
           pip install .[dev]
 
-      - name: Run canonical quality gate
+      - name: Install JS dependencies for changed-file gate and audit
+        run: npm ci --ignore-scripts
+
+      - name: Run changed-file quality gate on pull requests
+        if: github.event_name == 'pull_request'
+        shell: bash
+        run: |
+          set -o pipefail
+          python scripts/run_changed_quality_gate.py 2>&1 | tee quality-gate.log
+
+      - name: Run canonical quality gate on pushes
+        if: github.event_name == 'push'
         shell: bash
         run: |
           set -o pipefail
           python scripts/run_quality_gate.py --python-only --skip-tests 2>&1 | tee quality-gate.log
 
-      - name: Install JS dependencies for audit
-        run: npm ci --ignore-scripts
-
       - name: Audit JS dependencies
         run: npm audit --audit-level=high