docs(dependency-review): clarify allowed-bot-users trusted-users behavior

> [!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: `README.md`

## Summary

- update `gh-agent-workflows/dependency-review/README.md` to document that `allowed-bot-users` also maps to GH-AW `trusted-users` under `min-integrity: approved`
- align the inline guidance in `gh-agent-workflows/dependency-review/example.yml` with the same `allowed-bot-users` semantics

Closes \#2064.

## Validation

```bash
python3 scripts/check-nav-catalog.py
make docs-build # fails in strict mode due pre-existing unrelated docs warnings
bin/actionlint -ignore 'unknown permission scope "copilot-requests"' gh-agent-workflows/dependency-review/example.yml
```

---
[What is this?](https://ela.st/github-ai-tools) | [From workflow: Trigger Docs Patrol](https://github.com/elastic/ai-github-actions/actions/runs/34487869192)

Give us feedback! React with 🚀 if perfect, 👍 if helpful, 👎 if not.

---

> [!NOTE]
> This was originally intended as a pull request, but the git push operation failed.
>
> **Original error:** ERR_VALIDATION: pushSignedCommits: refusing unsigned push for branch 'docs/dependency-review-allowed-bot-users-2064-69fccc5b4272b5c6': Signed-commit payload violates file-protection policy (request_review): gh-agent-workflows/dependency-review/README.md
>
> **Workflow Run:** [View run details and download bundle artifact](https://github.com/elastic/ai-github-actions/actions/runs/34487869192)
>
> The bundle file is available in the `agent` artifact in the workflow run linked above.

To create a pull request with the changes:

```sh
# Download the artifact from the workflow run
gh run download 34487869192 -n agent -D /tmp/agent-34487869192

# Fetch the bundle into a temporary ref, then update the local branch
git fetch /tmp/agent-34487869192/aw-docs-dependency-review-allowed-bot-users-2064.bundle refs/heads/docs/dependency-review-allowed-bot-users-2064:refs/bundles/create-pr-docs-dependency-review-allowed-bot-users-2064-69fccc5b4272b5c6-12a43f65
git update-ref refs/heads/docs/dependency-review-allowed-bot-users-2064-69fccc5b4272b5c6 refs/bundles/create-pr-docs-dependency-review-allowed-bot-users-2064-69fccc5b4272b5c6-12a43f65
git checkout docs/dependency-review-allowed-bot-users-2064-69fccc5b4272b5c6
# Ensure the working tree matches the updated branch
git reset --hard
# Remove the temporary bundle ref
git update-ref -d refs/bundles/create-pr-docs-dependency-review-allowed-bot-users-2064-69fccc5b4272b5c6-12a43f65

# Push the branch to origin
git push origin docs/dependency-review-allowed-bot-users-2064-69fccc5b4272b5c6

# Create the pull request
gh pr create --title 'docs(dependency-review): clarify allowed-bot-users trusted-users behavior' --base main --head docs/dependency-review-allowed-bot-users-2064-69fccc5b4272b5c6 --repo elastic/ai-github-actions
```

Read gh-agent-workflows/dependency-review/README.md and example.yml to compare the existing allowed-bot-users guidance. Update both files so they document the mapping to GH-AW trusted-users under min-integrity: approved, then run scripts/check-nav-catalog.py and actionlint on the example workflow; docs-build may retain the noted unrelated strict-mode warnings.

Written by the indexing model from the issue text.