CI: add Lua syntax check workflow (luac5.4 -p over all .lua files)

.gitea/workflows/build.yml

@@ -0,0 +1,16 @@
+name: build
+on: [push, workflow_dispatch]
+
+jobs:
+  build-test:
+    runs-on: docker
+    container: debian:bookworm
+    timeout-minutes: 10
+    steps:
+      - name: Checkout
+        run: git clone --depth 1 ${{ github.server_url }}/${{ github.repository }}.git .
+
+      - name: Lua syntax check
+        run: |
+          apt-get update -qq && apt-get install -y -qq lua5.4
+          find . -name '*.lua' -not -path './.git/*' -print0 | xargs -0 -n1 luac5.4 -p