Admin user editing, knight-rider demos, self-contained user seeds

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

workspace/code/pattern_twinkle_demo.py

@@ -1,13 +1,41 @@
-"""Twinkle pattern demo using led_patterns helpers."""
+"""Twinkle NeoPixel demo — self-contained (stdlib + simulated hardware only)."""
+
+import random
+import time
 
 from machine import Pin
 import neopixel
-import time
 
-from led_patterns import twinkle_frame
+# --- helpers
 
 
-np = neopixel.NeoPixel(Pin(4), 36)
+def _clamp(channel: int) -> int:
+    return max(0, min(255, int(channel)))
+
+
+def twinkle_frame(
+    led_count: int,
+    frame: int,
+    base=(0, 0, 8),
+    sparkle=(255, 255, 180),
+    sparkles: int = 3,
+    seed: int = 1337,
+):
+    if led_count <= 0:
+        return []
+    out = [tuple(_clamp(v) for v in base) for _ in range(led_count)]
+    rng = random.Random(seed + frame)
+    for _ in range(min(max(0, sparkles), led_count)):
+        idx = rng.randrange(led_count)
+        out[idx] = tuple(_clamp(v) for v in sparkle)
+    return out
+
+
+# --- demo
+
+NUM_LEDS = 16
+
+np = neopixel.NeoPixel(Pin(4), NUM_LEDS)
 
 for frame in range(120):
     frame_colors = twinkle_frame(
@@ -15,7 +43,7 @@ for frame in range(120):
         frame,
         base=(0, 0, 6),
         sparkle=(255, 210, 130),
-        sparkles=5,
+        sparkles=3,
     )
     for i, color in enumerate(frame_colors):
         np[i] = color