ESP-IDF Integration:
- Add CMakeLists.txt and main/ component for ESP-IDF builds
- Add sdkconfig.defaults for each supported target (S3, C6, H2)
- Add Kconfig.projbuild for menuconfig integration

New Features:
- Interactive REPL over USB serial console
- Multi-line input with bracket/brace counting
- WS2812 RGB LED control via led.init()/rgb()/on()/off()
- Configurable JS heap size per target

Code Quality Improvements:
- Replace magic numbers with named constants (REPL_BUF_SIZE, etc.)
- Fix 64-bit format specifiers (PRIu32, PRIx32) for portability
- Remove code duplication in REPL loop
- Add CONFIG_LED conditional compilation for LED support
- Guard likely/unlikely macros to prevent redefinition

Build System:
- Add 'make esp32' target for generating 32-bit headers
- Add mqjs_led.o to host build with stub implementations
- Add comprehensive .gitignore for build artifacts

Documentation:
- Extensive ESP32 build instructions in README.md
- Troubleshooting guide for common issues
- USB connection explanations for different targets

- Implement mqjs_gpio.c/h with GPIO pin control API
- Support for input/output modes with pull-up/pull-down resistors
- JavaScript API: gpio.init(), gpio.write(), gpio.read(), gpio.setPull()
- Compatible with ESP32-S3, ESP32-C6, and ESP32-H2
- Follows same pattern as LED library with ESP_PLATFORM conditionals
- Add example blink_led.js script for simple LED control
- Update build system (CMakeLists.txt, Makefile) to include GPIO support
- Add comprehensive documentation in README-ESP32.md and BUILD_ESP32H2.md

# Conflicts:
#	mquickjs.c