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>

firmware/ws2812_led.h

@@ -0,0 +1,33 @@
+#ifndef WS2812_LED_H
+#define WS2812_LED_H
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifndef MAX_STRIPS
+#define MAX_STRIPS 8
+#endif
+
+/* Create strip slots (none active until ws2812_set_pin). max_leds = capacity each. */
+void ws2812_init(unsigned int max_leds);
+
+/* Bind strip to gpio (creates/rebinds PIO SM). strip = 0 … MAX_STRIPS-1. */
+int ws2812_set_pin(unsigned int strip, unsigned int pin);
+/* Free PIO SM + GPIO so another strip can take the pin. */
+void ws2812_release_strip(unsigned int strip);
+unsigned int ws2812_get_pin(unsigned int strip);
+int ws2812_strip_active(unsigned int strip);
+
+void ws2812_set_rgb(unsigned int strip, const uint8_t *rgb, unsigned int count);
+void ws2812_fill(unsigned int strip, uint8_t r, uint8_t g, uint8_t b);
+void ws2812_show(unsigned int strip);
+void ws2812_show_all(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif