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

Pipfile

@@ -17,7 +17,7 @@ websocket-client = "*"
 [dev-packages]
 
 [requires]
-python_version = "3.12"
+python_version = "3.11"
 
 [scripts]
 run = "python src/main.py"
@@ -27,4 +27,6 @@ sound = "python src/sound.py"
 dev-ui = 'watchfiles "python src/ui_client.py" src'
 dev-control = 'watchfiles "python src/control_server.py" src'
 install = "pipenv install"
+install-system = "bash -c 'sudo apt-get update && sudo apt-get install -y python3-spidev python3-pip python3-dev portaudio19-dev libasound2-dev'"
+monitor-esp32 = "bash -c 'source $HOME/esp/esp-idf/export.sh && cd esp32 && idf.py monitor'"
 send-json = "python test/send_json.py"