Check types in CI

Previously, the only enforcement of TypeScript was through ESLint rules
from @typescript-eslint.

.github/workflows/ci.yml

@@ -41,6 +41,16 @@ jobs:
       - run: npm run lint:static-site
       - run: node ./scripts/check-resource-index-match.js
 
+  type-check:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version-file: 'package.json'
+      - run: npm ci
+      - run: npm run type-check
+
   # Build into Heroku slug so we can deploy the same build that we test.
   build:
     runs-on: ubuntu-latest

package.json

@@ -17,6 +17,7 @@
     "lint": "npm run lint:server",
     "lint:server": "DEBUG=eslint:cli-engine npx eslint --max-warnings=0 --ext .js,.jsx .",
     "lint:static-site": "cd static-site && DEBUG=eslint:cli-engine npx eslint --max-warnings=0 --ext .js,.jsx,.ts,.tsx .",
+    "type-check": "cd static-site && tsc",
     "server": "node server.js",
     "groups": "node server.js --app ./src/groupsApp.js",
     "start": "npm run server",