Suggested test: copilot/assign-to-agent-reasoning-effort

## Motivation

Link to the gh-aw PR: github/gh-aw#60346 — Add reasoning effort support to assign-to-agent

`assign-to-agent` can now forward an optional, templatable `reasoning_effort` string through the agent assignment API. Unsupported agents/models/values emit a warning and continue without the field; supported values are sent as `agent_assignment.reasoning_effort`.

## Proposed test

- **Workflow file**: `test-copilot-assign-to-agent-reasoning-effort.md`
- **Trigger**: `workflow_dispatch`
- **Engine**: copilot
- **Safe output**: `assign-to-agent`
- **Variant**: standard

## Minimal test prompt sketch

Extend the existing `assign-to-agent` pattern (see `test-copilot-assign-to-agent.md`): configure `safe-outputs.assign-to-agent` with `reasoning_effort: high` (or via `${{ inputs.reasoning_effort }}`), create a sample issue, and assign the agent with the configured reasoning effort. Assert the workflow compiles and dispatches the field without error.

## New fixtures or secrets needed

None.

## Notes

`test-copilot-assign-to-agent.md` already exists but does not set `reasoning_effort`; this is additive coverage for the new field, not a duplicate. No overlapping open suggestion found.

> Generated by [🔍 Suggest New E2E Tests](https://github.com/githubnext/gh-aw-test/actions/runs/34683570501) · copilot · auto · 37.1 AIC · ⌖ 6.01 AIC · ⊞ 8.4K · [◷](https://github.com/search?q=repo%3Agithubnext%2Fgh-aw-test+is%3Aissue+%22gh-aw-workflow-call-id%3A+githubnext%2Fgh-aw-test%2Fsuggest-new-e2e-tests%22&type=issues)

Start with test-copilot-assign-to-agent.md and use it as the pattern for the new test-copilot-assign-to-agent-reasoning-effort.md workflow. Configure reasoning_effort, create a sample issue, and verify that the workflow compiles and dispatches the field without error; no new fixtures or secrets should be needed.

Written by the indexing model from the issue text.