Extract one shared command-queue helper for the *Ops runQueued/runCommitted copies #90

Problem

runCommitted now exists as four identical copies (ProjectOps, LoginOps, CredentialOps, ServiceOps), and six more *Ops types have a runQueued that already calls DoCommitted. The repo rule is to extract shared logic at three uses.

Fix

Add one package-level helper in cmd/relay (for example runOnQueue(q, ctx, fn, committed bool), or two small funcs) and have every *Ops call it. config_queue_structural_test.go matches the helper names in source text, so update it in the same change and check the scan still finds every call.

Found in the review of #87.