Implement version skip logic for re-processing

[FlatBallFlyer]

• Add skip logic to Version.process() method to check if version is already implemented
• Use VersionManager.get_current_version() to compare current vs target versions
• Skip processing if current version >= target version
• Add skip_reason data to events for better tracking
• Add comprehensive test for re-processing functionality
• Test verifies database state remains unchanged after re-processing
• Test detects skip events in processing results