compute-e2e-multi-app

End-to-end fixture for the Prisma Compute build pipeline (see services/build-runner/scripts/e2e/README.md in pdp-control-plane).

A repo whose root prisma.compute.json declares two apps (web and api, both minimal Hono servers). A build dispatched for this repo must:

1. discover the multi-app config and fan out one targeted build per app,
2. retire the discovering build as cancelled (Multi-app config: dispatched one build per app (web, api)),
3. produce two succeeded builds — an app per target, with api carrying its configured display name multi-app-api — each answering /health on its deployed URL,
4. leave no branch-named placeholder app behind.

Both apps bind Hono's framework-led port (:3000, not :8080 — the customer-app deploy path does not inject PORT). The config deliberately sets no region/httpPort overrides so the fixture stays deterministic across preview and production; exercise region fidelity with a temporary branch that adds an override.