Guard start_command_read_blocks against cards that place TOKEN_BLOCK_START so early that extra_data_size exceeds the bytes expected on the current iteration. Without this check, the unsigned subtraction for will_receive underflows and propagates into memset, SPI transaction length, and memcpy counts against the fixed 516-byte block buffer.
Ensure that enum values are used When assigning `pull_up_en` and `pull_down_en`
fields of `gpio_config_t`. Helps avoid `invalid conversion` errors when
building those code snippets in C++.