Fix wave chunk A: no Default option, composer = strong slot, catalog revalidation

Item 1 — no Default in the slot selectors (owner, fix wave): a
"default" model is not a thing in this app. Picking Default used to
delete the slot and re-arm the first-run gate — incoherent. Now the
model menus carry NO clear row at all (a slot holds a pick or reads
"—"), the thinking menus carry a "—" row (menu-none) that clears only
the thinking pin, and the hint line is the roster only — the resolved
factory pin is never named. Master's amendment confirmed: the
factory-pin hint is SUPERSEDED entirely (Platform removes the pins).

Item 2 — the composer control IS the strong slot (owner: "one and the
same"): ModelControl (model-picker.tsx) reads the raw models section
(GET /api/settings) and the federated catalog, and writes
PUT /api/settings/models via composeSlotModel — the same seam the
settings Agent section and SetupDialog use. Props retired: chatId,
settings, onSaved, fallbackModelId, noDefaultModel — the control is
self-sufficient and identical on every surface (composer, home dock,
/chat/new). The per-chat model PUT is gone from the UI; legacy
per-chat overrides keep resolving server-side. StatsBar/DockOverlay
plumbing slimmed accordingly; chat.tsx drops its per-chat settings
state and initialSettings prop.

Item 3 — the composer catalog cache no longer freezes per page load:
fetchCatalog(force) invalidates, and every model-menu open revalidates
in the background (stale-while-revalidate — cached list shows
instantly, the fresh federation swaps in). Owner's repro verified live:
a key saved mid-session widens the menu without a reload.

Item 4 — stale doc comments fixed: model-catalog.ts's "OpenRouter
catalog"/"multi-provider future" (Platform's file — mechanical,
flagged for review) and model-picker's retired "config-pinned"/
per-chat-PUT narrative.

Live-verified on 3001: unpicked slots read "—" everywhere; model
menus have no clear row; the "—" thinking row clears the pin but
keeps the model; composer pick writes strong and preserves cheap/
vision siblings; thinking pill writes strong.thinkingLevel; groq key
added mid-session appears in the open menu without reload. Caught in
live verification: the record fetch was mapping the WHOLE settings
record into the models section (picks never wrote) — fixed to read
body.settings.models.

Gates: typecheck, lint, 807/807, build.

app/chat/[id]/page.tsx

@@ -25,7 +25,6 @@ export default async function ChatPage({
 			// A teacher turn that outlived its client: the remounted view must
 			// attach (busy shimmer + poll), never resurrect the stale record.
 			initiallyInFlight={isTurnRunning(chat.id)}
-			initialSettings={chat.settings}
 		/>
 	);
 }