Subagent delegation hardcoded api_mode='chat_completions' for any
delegation.base_url that didn't match three specific hostnames
(chatgpt.com, api.anthropic.com, api.kimi.com/coding), and never
read delegation.api_mode from config. Azure AI Foundry's
https://foundry.services.ai.azure.com/anthropic endpoint fell through
and got chat_completions, causing 404s on every delegate_task call.
The main agent already handles this correctly via the shared
_detect_api_mode_for_url() helper (anything ending in /anthropic →
anthropic_messages); delegation reimplemented its own narrower check.
Reuse the shared detector and honor an explicit delegation.api_mode
when set so users can also force the transport on non-standard
endpoints the URL heuristic can't classify.
Fixes#10213.
Co-authored-by: HiddenPuppy <HiddenPuppy@users.noreply.github.com>
Teknium
c445f48b78