Reject empty result arrays so an empty eval run cannot pass CI

[royalpinto007]

Problem

POST /api/runs checks that results is an array, but accepts an empty array. The run is stored with total: 0, and the response reports shouldFail: false. A broken CI producer can therefore submit no evaluation cases and still get a passing gate.

Relevant code: app/api/runs/route.ts.

Expected behavior

An empty results array should return HTTP 400 with a clear validation error and should not create a suite or run.

Acceptance criteria

• Reject results: [] before any database write.
• Keep non-empty payload behavior unchanged.
• Add a regression test for the empty-array case.
• Document the requirement in the informational GET /api/runs response if needed.

[vsolano9]

I’m working on this. I’ll add a request-level regression test that proves an empty results array is rejected before any database access, keep non-empty ingestion unchanged, and update the informational endpoint so the requirement is explicit.