Fix matplotlib permission + HF cache dirs

Dockerfile

@@ -7,6 +7,11 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
     build-essential git && \
     rm -rf /var/lib/apt/lists/*
 
+# Writable dirs for matplotlib and HF cache
+ENV MPLCONFIGDIR=/tmp/matplotlib
+ENV HF_HOME=/tmp/hf_cache
+RUN mkdir -p /tmp/matplotlib /tmp/hf_cache
+
 # Python deps
 COPY requirements.txt .
 RUN pip install --no-cache-dir -r requirements.txt
@@ -14,7 +19,10 @@ RUN pip install --no-cache-dir -r requirements.txt
 # App code
 COPY . .
 
-# HF Spaces expects port 7860
+# Writable dirs for outputs
+RUN mkdir -p /app/models /app/outputs /app/logs /app/eval_logs && \
+    chmod -R 777 /app/models /app/outputs /app/logs /app/eval_logs /tmp/matplotlib /tmp/hf_cache
+
 EXPOSE 7860
 
 CMD ["python", "app.py"]