- Added `DisplayName` to model configuration for Codex, Claude, Gemini, Vertex, and OpenAI compatibility.
- Updated hash computation and model summary to account for `DisplayName`.
- Enhanced API handlers to use `DisplayName` for client-facing catalogs.
- Expanded tests to verify `DisplayName` usage, preservation, and fallback mechanisms.
- Updated documentation and configuration examples for `DisplayName` field.
Closes: #4245