Refactor 11 more tests to mcrfpy.step() pattern

Converted from Timer-based async to step()-based sync:
- test_simple_callback.py
- test_empty_animation_manager.py
- test_frame_clipping.py
- test_frame_clipping_advanced.py
- test_grid_children.py
- test_color_helpers.py
- test_no_arg_constructors.py
- test_properties_quick.py
- test_simple_drawable.py
- test_python_object_cache.py
- WORKING_automation_test_example.py

Only 4 tests remain with Timer-based patterns (2 are headless detection
tests that may require special handling).

🤖 Generated with Claude Code (https://claude.com/claude-code)

Co-Authored-By: Frack <frack@goblincorps.dev>
Co-Authored-By: Claude <noreply@anthropic.com>

tests/unit/test_simple_drawable.py

@@ -1,30 +1,32 @@
 #!/usr/bin/env python3
-"""Simple test to isolate drawable issue"""
+"""Simple test to isolate drawable issue
+Refactored to use mcrfpy.step() for synchronous execution.
+"""
 import mcrfpy
 import sys
 
-def simple_test(timer, runtime):
-    timer.stop()
-    
-    try:
-        # Test basic functionality
-        frame = mcrfpy.Frame(pos=(10, 10), size=(100, 100))
-        print(f"Frame created: visible={frame.visible}, opacity={frame.opacity}")
-        
-        bounds = frame.get_bounds()
-        print(f"Bounds: {bounds}")
-        
-        frame.move(5, 5)
-        print("Move completed")
-        
-        frame.resize(150, 150)
-        print("Resize completed")
-        
-        print("PASS - No crash!")
-    except Exception as e:
-        print(f"ERROR: {e}")
-    
-    sys.exit(0)
-
+# Initialize scene
 test = mcrfpy.Scene("test")
-simple_test_timer = mcrfpy.Timer("simple_test", simple_test, 100, once=True)
+test.activate()
+mcrfpy.step(0.01)
+
+try:
+    # Test basic functionality
+    frame = mcrfpy.Frame(pos=(10, 10), size=(100, 100))
+    print(f"Frame created: visible={frame.visible}, opacity={frame.opacity}")
+
+    bounds = frame.get_bounds()
+    print(f"Bounds: {bounds}")
+
+    frame.move(5, 5)
+    print("Move completed")
+
+    frame.resize(150, 150)
+    print("Resize completed")
+
+    print("PASS - No crash!")
+    sys.exit(0)
+except Exception as e:
+    print(f"ERROR: {e}")
+    print("FAIL")
+    sys.exit(1)