ci: add Python + engine type-check workflow

Author: Broccolito

.github/workflows/ci.yml

@@ -0,0 +1,45 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  python:
+    name: Python shim tests
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.11"
+      - name: Install package + dev deps
+        run: |
+          python -m pip install --upgrade pip
+          pip install -e ".[dev]"
+      - name: Run pytest
+        run: pytest -v
+
+  engine-typecheck:
+    name: Engine type-check
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: "22"
+      - name: Install engine deps
+        working-directory: engine
+        run: npm ci
+      - name: Type-check
+        working-directory: engine
+        run: |
+          if [ -f tsconfig.json ]; then
+            npx tsc --noEmit
+          else
+            echo "No tsconfig.json; skipping type-check."
+          fi