- Added optional `requestModelId` to the `Model` interface for upstream wire overrides.
- Prioritized `model.requestModelId` when resolving request model IDs for Anthropic and OpenAI paths.
- Used `COPILOT_API_HEADERS` in Copilot discovery and policy calls with API version `2026-06-01`.
- Synthesized Copilot `-1m` long-context sibling models with dedicated upstream IDs and pricing data.