### Motivation and Context
DevFlow currently starts PR reviews for all contributors. Align its
review eligibility with Microsoft Agent Framework by checking membership
in the internal developer team before running the review.
### Description
- Split the workflow into `prepare_pr`, `team_check`, and `review` jobs.
The review runs only when the team check succeeds.
- Check the **PR author** for automatic runs and the **person starting
the workflow** for manual runs. Draft PRs follow the same eligibility
check as other PRs.
- Add a team-membership helper that uses the team slug supplied by
`DEVELOPER_TEAM`, plus a `team-check` GitHub App token profile with
member and PR read permissions.
- Keep SK's existing spam/relevance check and DevFlow review steps.
- Add tests for the membership helper and token profile, and include the
helper in the automation test workflow's path filters.
---------
Co-authored-by: Copilot App <[email protected]>
### Motivation and Context
Semantic Kernel workflows currently depend on the user-scoped
`GH_ACTIONS_PR_WRITE` token for issue labels, pull-request labels, and
DevFlow GitHub API writes. Reduced PAT lifetimes make these automations
operationally fragile and require frequent manual rotation.
This change introduces the dedicated `semantic-kernel-automation` GitHub
App, installed only on `microsoft/semantic-kernel`, and uses short-lived
installation tokens signed through Azure Key Vault HSM. Fixes#14410.
### Description
- Add a reusable composite action that authenticates to Azure through
GitHub Actions OIDC, signs the GitHub App JWT through Key Vault without
exposing private-key material, and exchanges it for a repository-scoped
installation token.
- Mint least-privilege tokens for issue labeling, pull-request labeling,
and DevFlow repository operations.
- Migrate `label-issues.yml`, `label-pr.yml`, and
`devflow-pr-review.yml` to App-first authentication with the existing
PAT retained temporarily as a controlled rollout fallback.
- Keep DevFlow GitHub API writes on the App token while Copilot
continues to use the built-in Actions token with `copilot-requests:
write`.
- Add focused JavaScript tests for JWT construction, HSM signature
conversion, permission scoping, malformed configuration, and GitHub API
failures.
### Contribution Checklist
- [x] The code builds clean without any errors or warnings
- [x] The PR follows the [SK Contribution
Guidelines](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md)
and the [pre-submission formatting
script](https://github.com/microsoft/semantic-kernel/blob/main/CONTRIBUTING.md#development-scripts)
raises no violations
- [x] All unit tests pass, and I have added new tests where possible
- [x] I didn't break anyone 😄
Copilot-Session: d9fa4e9c-c32d-42fb-8ee4-4772473e6479
