Merge origin/master into worktree/web-plugin-config, adapting to ctx.remote.$on

#2201 landed three moves this branch sits on top of. `bindSettingsScope` became
`ctx.settingsScope.bind` on the Settings surface, so the section injects that
service and the Remote face instead of importing a free function; the
`SettingsScope` types moved into the runtime contract module, which is where
this branch's `base`, `user`, and `unset` now live; and the client
`credentials/changed` event became the forwarded owner event
`credentials/updated`, which the web-search card subscribes to through
`ctx.remote.$on`.

The generated module graph crossed mermaid's 1000-edge render guard with this
branch's 14 new edges. The guard doubles again, exactly as it did at 500 — the
graph counts real package edges, and trimming them to fit a renderer default
would make the document lie about the dependency set.

packages/client/ui-plugin-config/README.md

@@ -20,7 +20,7 @@ A card stages what the user types and writes it only when they save. Each contro
 
 Saving writes each staged field through the client settings scope, which fences every write with the namespace revision it read, so a form that has drifted from the document is refused rather than overwriting a concurrent change. The Host is the only authority on whether a value was accepted — its validators own the constraints no schema can express — so the card reads the section back afterwards and reports a save that did not land, keeping those drafts for the user to correct.
 
-A key can also be written from another surface — the Models page addresses the same reference — which changes no settings section, so the card re-reads on the Host's credential-changed signal for the reference it watches.
+A key can also be written from another surface — the Models page addresses the same reference — which changes no settings section, so the card re-reads on the forwarded `credentials/updated` event for the reference it watches.
 
 A field's presence in the raw user layer — not its value — is what marks it overridden; a reset clears that field so it re-inherits the composition layer. Secret-role fields never ride a response, so a key control starts blank, reports only whether one is configured, and writes through the credentials domain rather than the settings section; a blank draft writes nothing and keeps the stored key.