fix: add Chinese fonts (fonts-noto-cjk) for PDF/rendering

- Install Noto CJK fonts so Hermes can generate PDFs with Chinese text
- Run fc-cache to rebuild font cache after install

Dockerfile

@@ -1,9 +1,10 @@
 FROM python:3.12-slim
 
-# System deps
+# System deps + Chinese fonts
 RUN apt-get update && apt-get install -y --no-install-recommends \
     git curl gnupg2 \
-    && rm -rf /var/lib/apt/lists/*
+    fonts-noto-cjk \
+    && fc-cache -f && rm -rf /var/lib/apt/lists/*
 
 WORKDIR /app