- Fix X-Initiator detection: check for any assistant/tool role
in messages instead of only the last message role, matching
the correct agent detection for multi-turn tool conversations
- Add x-github-api-version: 2025-04-01 header for API compatibility
- Support Business/Enterprise accounts by using Endpoints.API from
the Copilot token response instead of hardcoded base URL
- Fix Responses API vision detection: detect vision content before
input normalization removes the messages array
- Add 8 test cases covering the above fixes
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>