Wave-5 chunk B: three model slots, search-engine row, first-run setup flow

Chunk B (owner-designed, model-slots wave) on the merged engine surface
(main 1d66a17):

AGENT SECTION — SLOTS ONLY (owner ruling)
- The six per-role model rows are GONE; three slot rows instead:
  Strong (Prober + Teacher), Cheap (five workhorse roles), Vision
  (visual maker + PDF reader), roster + resolved-default in every hint.
- Slot dropdowns share the app's menu language over the FEDERATED
  catalog (/api/models = keyed providers only, fresh per call — saving
  a key in Keys immediately widens the picker); the vision slot
  filters to image-capable models (Model.input); the menu's highlight
  now matches provider+id (ids can collide across providers).
- Slots write the new models section (PUT /api/settings/models) through
  the dialog's write seam; per-role overrides stay schema-only.
- ModelMenuList rows read 'provider · id' — federation makes the
  provider bookkeeping-relevant. Usage stamps render provider-qualified
  (prettyModel(qualified): 'Glm 5.3 Flash · openrouter') in the stats
  bar's turn lines.

SEARCH ENGINE (search wave: no default, owner)
- A row in Tools: Tavily/Brave via the shared-menu look, Automatic =
  the pin removed (auto-activation). The live reason line comes from
  /api/search; no engine key at all grays the whole row + disables the
  trigger (a keyless choice would only block auto-activation).

FIRST-RUN SETUP FLOW (owner design A: composer CTA + send interception)
- Chats cannot start until all three slots are picked — no defaults
  for 33 providers (slotsConfigured: all three slot models required).
- The graph view's new-session dock (home) shows a 'Set up your models'
  CTA while unconfigured; submitting a topic opens the SetupDialog WITH
  THE DRAFT PRESERVED; Save stores the models section and the queued
  message sends. Same interception on /chat/new sends.
- STAGED BY DEPENDENCY (owner: keys first, models after): no keyed
  provider → stage 1 deep-links the settings dialog on Keys (open now
  takes a section); a saved key reopens at stage 2 on the next submit.
- Stage 2: Strong → Cheap → Vision pickers (federated, vision-filtered,
  all three required). Closable without configuring — browsing stays
  possible; the gate is the send, not the dialog. Layered Esc: an open
  slot menu eats Esc before the dialog.
- Two closure bugs caught live: onDone→start/send captured the stale
  pre-save 'configured' (the flow now forces the replayed send); menu-Esc
  used to close the whole dialog.

Settings-dialog provider: open(section?) lands on a section (stage 1
deep-link). Tests: composeSlotModel/composeSearchEngine pure, slot SSR
replacing role rows, slotsConfigured/setupStage first-run gates,
provider-qualified prettyModel. Gates: typecheck, lint, 792/792, build.

components/new-session.tsx

@@ -9,6 +9,8 @@ import { GraphContextControl, effectiveContextTokens } from "@/components/graph-
 import { useDefaultSettings } from "@/components/default-settings";
 import { PhaseChip } from "@/components/phase-divider";
 import { SidebarToggle } from "@/components/sidebar";
+import { SetupDialog } from "@/components/setup-dialog";
+import { useSettingsDialog } from "@/components/settings/settings-dialog.tsx";
 import { StatsBar } from "@/components/stats-bar";
 import type { ChatSettings } from "@/src/core";
 
@@ -148,7 +150,13 @@ export function DraftShell({
 	);
 }
 
-export function NewSession({ initialSettings }: { initialSettings: ChatSettings | null }) {
+export function NewSession({
+	initialSettings,
+	initialConfigured,
+}: {
+	initialSettings: ChatSettings | null;
+	initialConfigured: boolean;
+}) {
 	const router = useRouter();
 	const [text, setText] = useState("");
 	const [busy, setBusy] = useState(false);
@@ -160,8 +168,22 @@ export function NewSession({ initialSettings }: { initialSettings: ChatSettings
 	// hands the choice up; it still rides the session POST then PUT-on-create.
 	const { settings, save: saveDraft } = useDefaultSettings(initialSettings);
 
-	const send = useCallback(() => {
+	// First-run gate (model-slots wave, owner 2026-09-20): the send
+	// INTERCEPTS into the setup flow while unconfigured — no defaults for
+	// 33 providers, chats cannot start. The draft stays in the textarea;
+	// Save completes and the send replays.
+	const [configured, setConfigured] = useState(initialConfigured);
+	const [setupOpen, setSetupOpen] = useState(false);
+	const { open: openSettings } = useSettingsDialog();
+
+	const send = useCallback((force = false) => {
 		if (!text.trim() || busy) return;
+		// `force` is the onDone path — the captured `configured` is still
+		// the pre-save value; the state update hasn't landed yet.
+		if (!configured && !force) {
+			setSetupOpen(true);
+			return;
+		}
 		setBusy(true);
 		void startDraftSession(text, settings, fetch)
 			.then((target) => {
@@ -169,16 +191,32 @@ export function NewSession({ initialSettings }: { initialSettings: ChatSettings
 				else setBusy(false);
 			})
 			.catch(() => setBusy(false));
-	}, [text, busy, settings, router]);
+	}, [text, busy, settings, router, configured]);
 
 	return (
-		<DraftShell
-			busy={busy}
-			text={text}
-			onChange={setText}
-			onSend={send}
-			settings={settings}
-			onSettingsSaved={saveDraft}
-		/>
+		<>
+			<DraftShell
+				busy={busy}
+				text={text}
+				onChange={setText}
+				onSend={send}
+				settings={settings}
+				onSettingsSaved={saveDraft}
+			/>
+			{/* First-run setup: the send interception's landing surface. */}
+			<SetupDialog
+				open={setupOpen}
+				onClose={() => setSetupOpen(false)}
+				onDone={() => {
+					setConfigured(true);
+					setSetupOpen(false);
+					send(true); // the queued draft sends
+				}}
+				onOpenKeys={() => {
+					setSetupOpen(false);
+					openSettings("keys");
+				}}
+			/>
+		</>
 	);
 }