- Prefix non-compliant message input IDs with `msg_` while leaving valid/prefixed IDs unchanged.
- Apply normalization before length checks and shortening to keep ID handling deterministic and consistent across Codex request paths.
- Updated `SanitizeCodexInputItemIDs` to remove encrypted reasoning items with IDs exceeding the Codex length limit.
- Refactored logic to deterministically shorten other overlong input item IDs, ensuring compliance with the Codex format.
- Added new tests to verify dropping behavior for encrypted reasoning and shortening of lengthy IDs without encrypted content.
- Implemented deterministic shortening of overlong Codex input item IDs to meet 64-character limit.
- Added `SanitizeCodexInputItemIDs` helper for efficient ID shortening in request bodies.
- Updated Codex executor and websocket implementations to utilize the new helper.
- Introduced unit tests to validate ID length restrictions, avoidance of collisions, and deterministic behavior.
Closes: #4401
