Suggested test: copilot/inline-sub-agent-kiwi-model

## Motivation

Link to gh-aw PR: github/gh-aw#43085 — feat: migrate 10 copilot sub-agents from `small` to `kiwi` / `mai-code`

This PR introduced the `kiwi` model alias (mapped to `copilot/kiwi*`, `openai/kiwi*`) and migrated several production workflows to it. The existing inline sub-agent smoke test (`test-copilot-inline-sub-agents.md`) uses `gpt-5-mini` and `claude-haiku-4.5` — it does not cover the new `kiwi` alias at all.

## Proposed test

- **Workflow file**: `test-copilot-inline-sub-agent-kiwi.md`
- **Trigger**: `workflow_dispatch`
- **Engine**: copilot
- **Safe output**: `create-issue`
- **Variant**: standard

## Minimal test prompt sketch

Declare one inline sub-agent with `model: kiwi`. The parent calls it with a fixed greeting and assembles the response into a `create-issue` body. This verifies that `kiwi` resolves at runtime and completes a turn without error.

## New fixtures or secrets needed

None — uses the existing `githubnext/gh-aw-test` repo. However, model availability needs triage: `kiwi` may not be resolvable in all CI runner environments. If unavailable, the test could be gated behind a `--use-samples` sample that bypasses the live engine call.

## Notes

- The existing `test-copilot-inline-sub-agents.md` already establishes the inline sub-agent fixture pattern; this would be a variant exercise only the new alias.
- `mai-code` (the other new alias from #43085) could be a third test candidate but is deferred here to keep scope minimal.
- Filed as an issue rather than a PR because `kiwi` model availability in the CI environment is uncertain and needs confirmation before adding a live-engine test.

> [!WARNING]
>
> Firewall blocked 1 domain
>
> The following domain was blocked by the firewall during workflow execution:
>
> - `awmgmcpg`
>> To allow these domains, add them to the `network.allowed` list in your workflow frontmatter:
>
> ```yaml
> network:
> allowed:
> - defaults
> - "awmgmcpg"
> ```
>
> See [Network Configuration](https://github.github.com/gh-aw/reference/network/) for more information.
>
>

> Generated by [🔍 Suggest New E2E Tests](https://github.com/githubnext/gh-aw-test/actions/runs/28651864364) · 97.7 AIC · ⌖ 8.93 AIC · ⊞ 5.6K · [◷](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 by reading test-copilot-inline-sub-agents.md and checking whether the CI environment can resolve the kiwi model alias. Add the proposed test-copilot-inline-sub-agent-kiwi.md workflow with workflow_dispatch, the copilot engine, and create-issue output; done means the inline sub-agent resolves kiwi and completes a turn without error.

Written by the indexing model from the issue text.