Converts tests from Timer-based async patterns to step()-based sync
patterns, eliminating timeout issues in headless testing.
Refactored tests:
- simple_timer_screenshot_test.py
- test_animation_callback_simple.py
- test_animation_property_locking.py
- test_animation_raii.py
- test_animation_removal.py
- test_timer_callback.py
Also updates KNOWN_ISSUES.md with comprehensive documentation on
the step()-based testing pattern including examples and best practices.
🤖 Generated with Claude Code (https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>