Fix /app/models directory permissions

- Create /app/models directory with write permissions
- Fixes PermissionError: [Errno 13] Permission denied: './models'

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Dockerfile

@@ -9,8 +9,8 @@ ENV MODEL_FILENAME=phi4-mini-instruct-Q4_K_M.gguf
 ENV USE_RAG=true
 ENV CACHE_ENABLED=true
 
-# Ensure /data directory exists and is writable
-RUN mkdir -p /data && chmod 777 /data
+# Ensure /data and /app/models directories exist and are writable
+RUN mkdir -p /data /app/models && chmod -R 777 /data /app/models
 
 EXPOSE 8000
 CMD ["python", "main.py"]