[Feature Request] Allow GitHub Apps to mint short-lived Copilot tokens for agentic workflows with per-app budget controls

**Summary**
We need a way for a GitHub App to mint a short-lived (≤ 6 hours) Copilot inference token so agentic workflows can consume Copilot AI Credits under a per-app budget cap, drawn from the organization's global Copilot AI Credits pool — rather than relying on the workflow-run GITHUB_TOKEN (no per-app control) or a user-owned PAT (COPILOT_GITHUB_TOKEN, seat-bound and operationally heavy).

**Background**
***How GitHub Agentic Workflows are billed today***
Running an agentic workflow (gh-aw) produces two cost streams: GitHub Actions minutes for compute, and AI inference charged by the model provider. For the default Copilot engine, there are two billing paths: [[github.github.com]](https://github.github.com/gh-aw/reference/billing/)

Organization billing — Inference is charged as AI Credits (AIC) against the organization's Copilot tenant. Requires (1) the org policy"Allow use of Copilot CLI billed to the organization" enabled, (2) copilot-requests: write declared under permissions: in the workflow frontmatter, and (3) the compiled .lock.yml committed. [[github.github.com]](https://github.github.com/gh-aw/reference/billing/)
Individual / seat billing — If those conditions aren't met, the workflow must be configured with a user-supplied COPILOT_GITHUB_TOKEN (fine-grained PAT). Inference is attributed to (and limited by) the PAT owner's Copilot entitlements. [[github.github.com]](https://github.github.com/gh-aw/reference/billing/), [[github.github.com]](https://github.github.com/gh-aw/reference/auth/)

GitHub recently removed the PAT requirement so agentic workflows can authenticate via the built-in GITHUB_TOKEN, eliminating the operational and security risks of managing long-lived PATs for automations at scale. [[github.blog]](https://github.blog/changelog/2026-06-11-agentic-workflows-no-longer-need-a-personal-access-token/), [[devops.com]](https://devops.com/github-removes-pat-requirement-for-agentic-workflows/)

***Current cost-control surface***

gh-aw exposes runtime guardrails such as max-ai-credits and max-daily-ai-credits, enforced per workflow run. [[github.github.com]](https://github.github.com/gh-aw/reference/billing/)
For org-level billing, GitHub's official guidance is to use cost centers (cost attribution to groups of organizations, with budgets applied to cost centers) plus the gh-aw cost-management tools to monitor and cap token usage per workflow run. The changelog explicitly notes:"User-level inference budgets are not considered when billing directly to the organization, because the cost is not attributed to a user." [[github.blog]](https://github.blog/changelog/2026-06-11-agentic-workflows-no-longer-need-a-personal-access-token/)
Copilot itself moved to usage-based AI Credits billing on June 1, 2026 (1 AIC = $0.01), with included credits pooled at the billing-entity level for Business/Enterprise plans. [[docs.github.com]](https://docs.github.com/en/copilot/concepts/billing/usage-based-billing-for-organizations-and-enterprises), [[github.blog]](https://github.blog/news-insights/company-news/github-copilot-is-moving-to-usage-based-billing/)

**Problem**
Neither billing path provides per-application budget control for agentic workflows:

GITHUB_TOKEN (org billing path) is global to the org — there is no built-in mechanism to control how many AI Credits a specific workflow or a specific GitHub App consumes from the org-wide pool. Cost centers operate at the org level, not the app level. [[github.blog]](https://github.blog/changelog/2026-06-11-agentic-workflows-no-longer-need-a-personal-access-token/)
COPILOT_GITHUB_TOKEN (seat billing path) ties spend to an individual user's Copilot seat, with all the PAT lifecycle/rotation/attrition overhead, and does not represent application-level ownership. [[github.github.com]](https://github.github.com/gh-aw/reference/billing/), [[github.github.com]](https://github.github.com/gh-aw/reference/auth/)
max-ai-credits / max-daily-ai-credits are enforced by gh-aw at the workflow-run level, not at the GitHub App level — so a single app running many workflows across many repos can still exceed any intended app-level budget. [[github.github.com]](https://github.github.com/gh-aw/reference/billing/)

This is a blocker for scaling agentic workflows safely across hundreds of applications/repos in a large enterprise, where we need to attribute and cap inference spend per automation system, not per user or per single run.

**Proposed Solution**
Allow a GitHub App to request a short-lived Copilot inference token for agentic workflow use, with the following properties:

1. Token issuance by GitHub App
- GitHub App can mint a Copilot token with a configurable TTL up to 6 hours.
- Token is ephemeral, scoped to the issuing App installation, and consumable by gh-aw (or other Copilot-CLI–based runners) in place of GITHUB_TOKEN / COPILOT_GITHUB_TOKEN.
2. Per-app AI Credits cap- Org admins can assign AIC caps (per-run, per-day, per-month) to each GitHub App.
- The cap draws from the organization's global Copilot AI Credits pool (not tied to any user seat).
- Once an app's cap is exhausted, further token issuance is denied with a clear error.
3. Cost center attribution at the App level
- Each GitHub App can be tagged with a cost center, so all inference spend is attributed at the app level in org-wide AIC reporting — extending the current cost-center model down from org → app. [[github.blog]](https://github.blog/changelog/2026-06-11-agentic-workflows-no-longer-need-a-personal-access-token/)
4. Audit & observability
- Token issuance, AIC consumption, and cap breaches are logged and surfaced in the existing Copilot billing/usage reports and gh aw audit output.

The issue names no repository files, tests, or implementation entry points. Start by reviewing the linked gh-aw billing and auth references and comparing the current GITHUB_TOKEN and COPILOT_GITHUB_TOKEN paths. Done would require agreed acceptance criteria for App token issuance, budget enforcement, attribution, and audit reporting.

Written by the indexing model from the issue text.