Add support for extracting binary files (PDFs, images, etc.) from the E2B
sandbox in ClaudeCodeBlock.
Changes:
- Add binary_extensions set for common binary file types (.pdf, .png, .jpg, etc.)
- Update FileOutput schema with is_binary and content_base64 fields
- Binary files are read as bytes and base64-encoded before returning
- Text files continue to work as before with is_binary=False
Closes SECRT-1897