Ensure cache is writtable

Dockerfile

@@ -19,8 +19,9 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 COPY requirements.txt .
 RUN pip install --upgrade pip && pip install --no-cache-dir -r requirements.txt
 
-# Create writable model cache directory to avoid permission error
-RUN mkdir -p /app/model_cache /app/.cache/huggingface
+# Create writable model cache directory and set correct ownership
+RUN mkdir -p /app/model_cache /app/.cache/huggingface && \
+    chown -R 1000:1000 /app/model_cache /app/.cache/huggingface
 
 # Copy app source code
 COPY . .