What each log subject is, and what it can and cannot do

The subject registry as data, so the UI never hardcodes a capability.

Every gap in the capability matrix was introduced by a change that shipped one channel and left the others, and the frontend then encoded that gap by hand: isTextReevalDisabled = channel === "text" outlived the PR that made text re-evaluation work by five phases, and its tooltip still cited that PR as pending. A control drawn from this response cannot outlive the truth, because there is only one declaration behind it.

No tenant data is involved — the registry is identical for every caller — so the response is a pure function of module-level declarations.