fix(patterns): correct non-blocking timing and blink off phase

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

src/patterns/marquee.py

@@ -17,9 +17,10 @@ class Marquee:
             now = utime.ticks_ms()
             if utime.ticks_diff(now, last) >= d:
                 c = self.driver.apply_brightness(colors[0], preset.b)
+                bg_color = self.driver.apply_brightness(colors[-1], preset.b)
                 for i in range(self.driver.num_leds):
                     m = (i + phase) % (on_len + off_len)
-                    self.driver.n[i] = c if m < on_len else (0, 0, 0)
+                    self.driver.n[i] = c if m < on_len else bg_color
                 self.driver.n.write()
                 phase = (phase + step) % (on_len + off_len)
                 self.driver.step = phase