ci: add GitHub Actions workflow for catalog validation

.github/workflows/validate.yml

@@ -0,0 +1,23 @@
+name: Validate Catalog
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  validate:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-python@v5
+        with:
+          python-version: "3.11"
+
+      - name: Install dependencies
+        run: pip install toml
+
+      - name: Validate catalog
+        run: python scripts/validate.py