ci(mindmodel): add scheduled validation workflow

.github/workflows/mindmodel-schedule.yml

@@ -0,0 +1,35 @@
+name: mindmodel scheduled validate
+
+on:
+  schedule:
+    - cron: '0 0 * * 0' # weekly
+
+jobs:
+  validate:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v4
+        with:
+          python-version: '3.11'
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install -r requirements.txt || true
+
+      - name: Run tests
+        run: |
+          python -m pytest -q
+
+      - name: Run mindmodel validator if manifest exists
+        if: ${{ always() }}
+        run: |
+          if [ -f .mindmodel/manifest.yaml ]; then
+            python -m scripts.mindmodel.cli || true
+          else
+            echo "No .mindmodel/manifest.yaml present — skipping validator"
+          fi

tests/ci/test_schedule_exists.py

@@ -0,0 +1,11 @@
+import pathlib
+
+
+def test_schedule_workflow_exists():
+    path = pathlib.Path(".github/workflows/mindmodel-schedule.yml")
+    assert path.exists(), f"Expected {path} to exist"
+
+    text = path.read_text(encoding="utf-8")
+    # ensure the file is a GitHub Actions workflow that declares a schedule
+    assert "on:" in text
+    assert "schedule" in text