December 2025 monthly summary for reportportal/service-api: Stabilized user assignment workflow by implementing case-insensitive validation to correctly handle duplicates with varying casing, preventing erroneous assignment errors and improving reliability. Key features delivered: - Case-insensitive user assignment validation to correctly identify already-assigned users when usernames differ only in case. - Strengthened data integrity in the user management flow, reducing edge-case failures in production. Major bugs fixed: - Fixed a case-sensitive check that caused incorrect errors for duplicate usernames during user assignment (commit f66789506fc719ca5a1ce1b0799a757e8002d05f). Overall impact and accomplishments: - Improved reliability of the user assignment pipeline, reducing runtime errors and potential user-facing failures in scenarios with duplicate usernames differing only by case. - Enhanced system stability for the service-api with a focused, low-risk bug fix that guards against data inconsistencies. Technologies/skills demonstrated: - Backend validation logic and case-insensitive comparison patterns - Traceable change via commit history and focused bug-fix workflow - Conservative, targeted risk mitigation with a single-issue fix