- Added post_build_merge.py script with ESP32 variant auto-detection
- Integrated post-build script to all platformio.ini environments
- Generates factory.bin (complete from 0x0) and firmware.bin (app only from 0x10000)
- Auto-detects ESP32/S2/S3/C3 by analyzing bootloader signature
- Organizes output by firmware version in firmware/{version}/ folders