ci: add missing proto.yml file

.github/workflows/proto.yml

@@ -0,0 +1,27 @@
+# Check if the generated protobuf code matches the committed code
+name: Protobuf
+on:
+  workflow_call:
+
+jobs:
+  proto-gen:
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    steps:
+      - uses: actions/checkout@v4
+      - name: "Check protobuf generated code matches committed code"
+        # yamllint disable
+        run: |
+          set -euo pipefail
+
+          make proto-gen
+
+          if ! git diff --stat --exit-code ; then
+            echo ">> ERROR:"
+            echo ">>"
+            echo ">> Protobuf generated code requires update (either tools or .proto files may have changed)."
+            echo ">> Ensure your tools are up-to-date, re-run 'make proto-gen' and update this PR."
+            echo ">>"
+            exit 1
+          fi
+        # yamllint enable