- Add `machine_esp32c3_flash.go` to implement the `BlockDevice` interface for ESP32-C3.
- Map internal ESP ROM SPI flash and cache invalidation functions via CGo.
- Update `targets/esp32c3.ld` to expose `__flash_data_start` and `__flash_data_end` linker variables.
- Add `esp32c3` to build tags in `src/machine/flash.go`.
- Ensure atomic flash operations by disabling interrupts and invalidating cache to prevent stale reads.
Signed-off-by: deadprogram <ron@hybridgroup.com>
deadprogram