Verify every integration boundary before blaming the client plugin

Decompose a client-visible integration failure before blaming installation or browser injection. Confirm, in order, that the client reaches the product endpoint, product authentication succeeds, the upstream dependency accepts its session, and the workflow persists its terminal artifact.

High request volume proves activity, not health; a functioning client can repeatedly poll a route that deterministically fails upstream. Treat implemented, deployed, and live-success verified as separate states after any retry or reauthentication patch.

This method localizes a boundary but does not explain why an upstream provider rejects a refreshed session; that requires provider and configuration evidence.