ci: Run prettier in check mode upon PRs

and pushes against an on master.

.github/workflows/prettier.yml

@@ -0,0 +1,28 @@
+name: Verify repo is prettier consistent
+
+on:
+    push:
+        branches:
+            - master
+    pull_request:
+        branches:
+            - master
+
+jobs:
+    build_and_verify:
+        runs-on: ubuntu-latest
+
+        steps:
+            - name: Checkout code
+              uses: actions/checkout@v3
+
+            - name: Set up Node.js
+              uses: actions/setup-node@v3
+              with:
+                  node-version: "23"
+
+            - name: Install dependencies
+              run: npm install
+
+            - name: Run prettier in check mode
+              run: node_modules/prettier/bin/prettier.cjs . --check