feat(ui-models): tag the provider rows this deployment declared

A row's stored profile could not tell a hand-declared gateway from a
shipped provider whose models someone narrowed — both look identical from
outside the adapter — so the Models page had no way to mark the routes a
deployment added itself.

The directory entry now carries `declared`, answered by the owning adapter
against its own installed catalog, and the page renders a Custom tag from
it. Absence stays "this adapter draws no such distinction" rather than
"shipped", so a route no adapter claims is labelled neither way.

Also records the default-route work's Agent Note and the e2e evidence for
all three changes: the composer switch writing the section, and the Models
page declaring a route with its own reasoning effort.

docs/core-data-structures/core.i18n.yaml

@@ -2,5 +2,5 @@
 # side as of the last confirmed-consistent state. Both languages carry equal authority;
 # after editing either side, bring the other along and re-record with:
 #   pnpm run verify-translation-pairing --write docs/core-data-structures/core.md
-core.md: 52e77be89d939eefa2b42ef5586c5798e194a303
-core.zh.md: 5f0134a4c8b3dead49830b41f62e8b7238327cfa
+core.md: eb96988abe096455c4f24ac220a6da3f266e690d
+core.zh.md: 7334b3d3a5bd088f5467a72d7357f87c4c745487