feat(simulator): add GUI runner, stubs, and workspace assets

Add host simulator scaffolding, examples, and docs so led-driver main can run end-to-end with MicroPython module stubs.

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

stubs/utime.py

@@ -0,0 +1,22 @@
+"""CPython stub for MicroPython `utime` (led-simulator)."""
+
+import time
+
+_MS_MASK = (1 << 30) - 1
+
+
+def sleep_ms(ms):
+    time.sleep(max(0, ms) / 1000.0)
+
+
+def sleep(s):
+    time.sleep(s)
+
+
+def ticks_ms():
+    return int(time.monotonic() * 1000) & _MS_MASK
+
+
+def ticks_diff(t1, t0):
+    """Approximate MicroPython ticks_diff for host monotonic ms."""
+    return ((t1 - t0 + (1 << 29)) & _MS_MASK) - (1 << 29)