docker: install media-types to fix content-type for fonts

starlette guesses the mimetype, but without media-types it doesn't
know anything about fonts

Dockerfile

@@ -1,5 +1,9 @@
 FROM python:3.11-slim-bookworm
 
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    media-types \
+    && rm -rf /var/lib/apt/lists/*
+
 RUN python -m pip install "poetry==1.8.2"
 
 COPY . /app