- Introduced `/openai/v1/videos` endpoint to support OpenAI-specific video generation. - Added error normalization and handling for OpenAI video resources, including detailed error propagation. - Enhanced response structure to include OpenAI-specific fields for status, progress, and model mappings. - Implemented new handlers for video content retrieval and error scenarios. - Expanded test coverage to validate OpenAI video support, error handling, and backend compatibility.