Add Pico presets engine, patterns, and tests.

Wire the Pico to UART-driven preset selection, add pattern modules and presets data, remove old p2p/settings code, and update tests and LED driver.

Made-with: Cursor

pico/test/test_serial_send.py

@@ -0,0 +1,23 @@
+#!/usr/bin/env python3
+"""
+Serial send test – single file. Run on ESP32 (TX side).
+Wire: ESP32 TX (GPIO17) → Pico RX (GPIO1); GND ↔ GND. Run receive test on Pico.
+  mpremote run pico/test/test_serial_send.py
+"""
+import time
+import sys
+from machine import UART, Pin
+
+if "esp32" in sys.platform:
+    UART_ID, TX_PIN, BAUD = 1, 17, 115200
+else:
+    UART_ID, TX_PIN, BAUD = 0, 0, 115200
+
+print("UART send: %s UART%d TX=%s %d baud" % (sys.platform, UART_ID, TX_PIN, BAUD))
+uart = UART(UART_ID, baudrate=BAUD, tx=Pin(TX_PIN, Pin.OUT))
+for line in [b"serial send test 1", b"serial send test 2", b"{\"v\":\"1\",\"b\":128}"]:
+    uart.write(line + b"\n")
+    print("sent:", line.decode("utf-8"))
+    time.sleep_ms(50)
+uart.deinit()
+print("Send test done.")