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.pio

@@ -0,0 +1,44 @@
+;
+; WS2812 PIO — from https://github.com/ForsakenNGS/Pico_WS2812
+;
+.program ws2812
+.side_set 1
+
+.define public T1 2
+.define public T2 5
+.define public T3 3
+
+.lang_opt python sideset_init = pico.PIO.OUT_HIGH
+.lang_opt python out_init = pico.PIO.OUT_HIGH
+.lang_opt python out_shiftdir = 1
+
+.wrap_target
+bitloop:
+    out x, 1               side 0 [T3 - 1]
+    jmp !x send_zero       side 1 [T1 - 1]
+send_one:
+    jmp bitloop            side 1 [T2 - 1]
+send_zero:
+    nop                    side 0 [T2 - 1]
+.wrap
+
+% c-sdk {
+#include "hardware/clocks.h"
+
+static inline void ws2812_program_init(PIO pio, uint sm, uint offset, uint pin, float freq, uint bits) {
+    pio_gpio_init(pio, pin);
+    pio_sm_set_consecutive_pindirs(pio, sm, pin, 1, true);
+
+    pio_sm_config c = ws2812_program_get_default_config(offset);
+    sm_config_set_sideset_pins(&c, pin);
+    sm_config_set_out_shift(&c, false, true, bits);
+    sm_config_set_fifo_join(&c, PIO_FIFO_JOIN_TX);
+
+    int cycles_per_bit = ws2812_T1 + ws2812_T2 + ws2812_T3;
+    float div = (float)clock_get_hz(clk_sys) / (freq * (float)cycles_per_bit);
+    sm_config_set_clkdiv(&c, div);
+
+    pio_sm_init(pio, sm, offset, &c);
+    pio_sm_set_enabled(pio, sm, true);
+}
+%}