Fix diffvg build: clone tag v0.1.0 correctly

Dockerfile

@@ -28,7 +28,12 @@ RUN pip install --upgrade pip \
  && pip install --no-cache-dir -r requirements.txt
 
 # —— Build diffvg from a known-good commit ——————————
-RUN git clone --filter=blob:none --depth 1 https://github.com/BachiLi/diffvg.git /tmp/diffvg \ && cd /tmp/diffvg \ && git fetch --depth 1 origin tag v0.1.0 \ && git checkout v0.1.0 \ && git submodule update --init --recursive \ && python setup.py install --user \ && cd /app && rm -rf /tmp/diffvg
+RUN git clone --depth 1 --branch v0.1.0 https://github.com/BachiLi/diffvg.git /tmp/diffvg \
+ && cd /tmp/diffvg \
+ && git submodule update --init --recursive \
+ && python setup.py install --user \
+ && cd /app \
+ && rm -rf /tmp/diffvg
 
 # —— Project code ————————————————————————————
 COPY --chown=appuser . /app