fix: update Dockerfile to clone wokwi-libs directly and streamline build process

.github/workflows/docker-publish.yml

@@ -20,8 +20,6 @@ jobs:
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4
-        with:
-          submodules: recursive
 
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3

Dockerfile.standalone

@@ -3,18 +3,21 @@ FROM node:20 AS frontend-builder
 
 WORKDIR /app
 
+# Clone wokwi-libs fresh from upstream to avoid stale submodule pointers.
+# git is pre-installed in the node:20 Debian image.
+RUN git clone --depth=1 https://github.com/wokwi/avr8js.git wokwi-libs/avr8js \
+ && git clone --depth=1 https://github.com/wokwi/rp2040js.git wokwi-libs/rp2040js \
+ && git clone --depth=1 https://github.com/wokwi/wokwi-elements.git wokwi-libs/wokwi-elements
+
 # Build avr8js
-COPY wokwi-libs/avr8js/ wokwi-libs/avr8js/
 WORKDIR /app/wokwi-libs/avr8js
 RUN npm install && npm run build --if-present
 
-# Build rp2040js (submodule may be empty on CI; skip if no package.json)
-COPY wokwi-libs/rp2040js/ wokwi-libs/rp2040js/
+# Build rp2040js (may have no build script on some commits)
 WORKDIR /app/wokwi-libs/rp2040js
-RUN if [ -f package.json ]; then npm install && npm run build --if-present; fi
+RUN npm install && npm run build --if-present
 
 # Build wokwi-elements
-COPY wokwi-libs/wokwi-elements/ wokwi-libs/wokwi-elements/
 WORKDIR /app/wokwi-libs/wokwi-elements
 RUN npm install && npm run build --if-present