Relocate bundled demo sources into bundled-demos/demo/

Mirror bundled-lib/ by keeping manifest.json at the bundle root and
shipping sample .py files from a demo/ subdirectory.

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

src/static/bundled-demos/demo/neopixel_demo.py

@@ -0,0 +1,12 @@
+"""Example ESP32 NeoPixel script using mock modules in browser."""
+
+from machine import Pin
+import neopixel
+
+
+np = neopixel.NeoPixel(Pin(4), 8)
+np.fill((0, 0, 0))
+np[0] = (255, 0, 0)
+np[1] = (0, 255, 0)
+np[2] = (0, 0, 255)
+np.write()