July 2025: Delivered core time handling overhaul across traPtitech/Jomon, standardized nullable time semantics (NullTime), unified DeletedAt/PaidAt handling, and aligned time conversions across models and services to improve data integrity and reduce runtime panics. Refactored API surface names for clarity and consistency, updated test mocks/infrastructure to stay in sync with tooling, and addressed deployment and performance improvements across two repositories. Fixed critical Docker deployment to run the correct binary in traO-Judge-judge, and implemented a memory-efficient session_id handling to reduce allocations. Overall, these changes enhanced data reliability, system stability, and developer velocity with tangible business value.