CI: phi-loop-ci workflow invalid (empty step blocks all jobs)

[gHashTag]

Problem

After #152 merged, .github/workflows/phi-loop-ci.yml contained a step with only name: and no run:/uses:. GitHub Actions rejects the workflow (no jobs scheduled).

Fix

Remove the orphan step; keep a single Ensure tri shim is executable step.

Refs

• feat(ring-46): E2E CI loop — Closes #150 #152, E2E CI: seed.t27 → t27c gen → zig test → GREEN #150 (E2E content landed; YAML fix is follow-up)