Replace MicroPython runtime with Pico C + W5500 firmware.

Ship UDP RGB panel firmware (eight WS2812 strips) and drop the ESP32 Wi-Fi/MicroPython stack.

Co-authored-by: Cursor <cursoragent@cursor.com>

.gitignore

@@ -1,10 +1,17 @@
-# Build files
+# Firmware build
+firmware/build/
 build/
 sdkconfig
 sdkconfig.old
 
+# Local make / deploy config
+.env
+
 # Binary files
 *.bin
+*.uf2
+*.elf
+*.hex
 
 # Python
 __pycache__/
@@ -16,7 +23,6 @@ env/
 venv/
 *.egg-info/
 dist/
-build/
 
 # IDE
 .vscode/