refactor(led-driver): simplify websocket runtime and test layout

tests/patterns/off.py

@@ -0,0 +1,30 @@
+#!/usr/bin/env python3
+import utime
+from machine import WDT
+from settings import Settings
+from presets import Presets, run_tick
+
+
+def main():
+    s = Settings()
+    pin = s.get("led_pin", 10)
+    num = s.get("num_leds", 30)
+
+    p = Presets(pin=pin, num_leds=num)
+    wdt = WDT(timeout=10000)
+    
+    # Create an "off" preset (use short-key field `p` for pattern)
+    p.edit("test_off", {"p": "off"})
+    p.select("test_off")
+
+    start = utime.ticks_ms()
+    while utime.ticks_diff(utime.ticks_ms(), start) < 200:
+        wdt.feed()
+        run_tick(p)
+        utime.sleep_ms(10)
+
+
+if __name__ == "__main__":
+    main()
+
+