Add ESP32-C3 SPI slave with ESP-NOW, Raspberry Pi test tools, and updated project structure

- ESP32-C3 SPI slave project with ESP-NOW broadcast functionality
- Raspberry Pi SPI master test tools and CLI for JSON communication
- Merged src/ directory from full branch with lighting controller code
- Updated Pipfile with system install scripts and ESP32 monitoring
- Added comprehensive test suite for SPI communication

esp32/main/CMakeLists.txt

@@ -0,0 +1,2 @@
+idf_component_register(SRCS "main.c"
+                    INCLUDE_DIRS ".")