Fix TranslateNonStream parameter order in all executors

fix: add Copilot-Vision-Request header for vision requests

fix(executor): include requested model in payload configuration

feat(registry): add supported endpoints for GitHub Copilot models

feat(executor): add HttpRequest method with credential injection for GitHub Copilot and Kiro executors

feat(executor): refine payload handling by integrating original request context

refactor(executor): improve concurrency and code quality in GitHub Copilot executor

feat(auth): add GitHub Copilot authentication and API integration