Add test-copilot-create-issue-body-footer for create-issue body-footer safe-output

> [!CAUTION]
> Protected files were modified in this change.
> This pull request is in `request_review` mode and requires explicit human scrutiny before merge.
>
> Protected files: `.github/workflows/test-copilot-create-issue-body-footer.md`

## Motivation

github/gh-aw#58841 added `body-footer` (with `{workflow_name}` / `{run_url}` placeholder support) to the `create-issue` and `create-pull-request` safe outputs, allowing workflow authors to append deterministic footer content regardless of agent-generated body content. No existing test in this repo exercises `body-footer`.

## What this adds

- **Workflow file**: `.github/workflows/test-copilot-create-issue-body-footer.md`
- **Trigger**: `workflow_dispatch`
- **Engine**: copilot
- **Safe output**: `create-issue` with a `body-footer:` template using the `{workflow_name}` and `{run_url}` placeholders
- **Variant**: standard (matches naming convention `test--.md`; the harness's `*"create-issue"*` case in `e2e.sh` will pick this test up for dispatch + `validate_issue_created` validation like the existing `test-copilot-create-issue.md`)

It includes a `samples:` block so it runs deterministically under `--use-samples`.

## Notes

- No new fixtures or secrets required — reuses the main `githubnext/gh-aw-test` repo.
- Only the `.md` source is included; the `.lock.yml` was not generated in this sandbox because the `gh aw` extension isn't installed here — the maintainer or CI can run `gh aw compile .github/workflows/test-copilot-create-issue-body-footer.md` to produce it before merge (per AGENTS.md §4/§13).
- This does not assert on the exact footer text content beyond visual inspection during manual/local triage; e2e.sh's existing `validate_issue_created` check (title-prefix + labels) is reused as-is, so the footer rendering itself is a design/behavior check rather than a strict harness assertion for now.

---

> [!NOTE]
> This was originally intended as a pull request, but the git push operation failed.
>
> **Original error:** The process '/usr/bin/git' failed with exit code 1
>
> **Workflow Run:** [View run details and download bundle artifact](https://github.com/githubnext/gh-aw-test/actions/runs/34205516021)
>
> The bundle file is available in the `agent` artifact in the workflow run linked above.

Create the pull request manually

```sh
# Download the artifact from the workflow run
gh run download '34205516021' -n agent -D '/tmp/agent-34205516021'

# Resolve the bundle source ref, fetch it into a temporary ref, then create the local branch
bundle_path='/tmp/agent-34205516021/aw-test-copilot-create-issue-body-footer.bundle'
temp_ref='refs/bundles/create-pr-test-copilot-create-issue-body-footer-bd875764441ffdc1-722f1e6c'
target_ref='refs/heads/test-copilot-create-issue-body-footer-bd875764441ffdc1'
bundle_source_ref=$(git bundle list-heads "$bundle_path" | awk '$2 ~ /^refs\/heads\// { print $2 }')
if [ -z "$bundle_source_ref" ]; then
bundle_source_ref=$(git bundle list-heads "$bundle_path" | awk '$2 == "HEAD" { print $2 }')
fi
if [ "$(printf '%s\n' "$bundle_source_ref" | sed '/^$/d' | wc -l | tr -d ' ')" != "1" ]; then
echo "Expected exactly one bundle source ref, found: $bundle_source_ref" >&2
exit 1
fi
git fetch "$bundle_path" "${bundle_source_ref}:${temp_ref}"
git update-ref "$target_ref" "$temp_ref"
git checkout 'test-copilot-create-issue-body-footer-bd875764441ffdc1'
# Ensure the working tree matches the updated branch
git reset --hard
# Remove the temporary bundle ref
git update-ref -d "$temp_ref"

# Push the branch to the target remote
git push 'origin' 'test-copilot-create-issue-body-footer-bd875764441ffdc1'

# Create the pull request
gh pr create --title 'Add test-copilot-create-issue-body-footer for create-issue body-footer safe-output' --base 'main' --head 'test-copilot-create-issue-body-footer-bd875764441ffdc1' --repo 'githubnext/gh-aw-test'
```

> Generated by [🔍 Suggest New E2E Tests](https://github.com/githubnext/gh-aw-test/actions/runs/34205516021) · copilot · auto · 59.9 AIC · ⌖ 10.9 AIC · ⊞ 8.8K · [◷](https://github.com/search?q=repo%3Agithubnext%2Fgh-aw-test+%22gh-aw-workflow-id%3A+suggest-new-e2e-tests%22&type=pullrequests)

Start with .github/workflows/test-copilot-create-issue-body-footer.md and compare it with test-copilot-create-issue.md, then inspect the matching create-issue case and validate_issue_created logic in e2e.sh. Run gh aw compile on the workflow as described in AGENTS.md, and verify that the dispatched workflow is picked up and passes the existing issue validation under --use-samples.

Written by the indexing model from the issue text.