BYOK universal gate rendered honestly: mid-chat setup flow, refusal-aware cards

- existing sessions: a send that lands the 503 models_not_configured envelope
  renders as the SETUP FLOW, never the error banner — the record refetch drops
  the refused orphan (the gate refuses before the write-ahead persist), the
  draft goes home to the composer, and Save auto-replays it (owner ruling);
  parseModelsRefusal reads the envelope from the transport's verbatim error
  text (exported pure, tested)
- persistent 'Set up your models' CTA above the chat composer while
  slotsConfigured is false (server-read seed via app/chat/[id]/page.tsx) —
  legacy per-chat overrides may still send with the pill present; the server
  gate stays the truth
- SetupDialog prefill + 'needed' marks (owner ruling): pinned tiers open with
  their pick (matched in the federated catalog — lapsed keys don't prefill),
  unpinned tiers carry the mark; Save still requires all three;
  prefillFromSlots exported pure, tested
- refused jobs read as INFO: dispatch card shows a quiet 'needs model setup'
  line + 'Set up models' deep-link (ChatActionsContext.openSetup); dock blobs'
  activity reads 'needs model setup' instead of 'failed'; real failures keep
  the red tone; isModelsRefusal added to the envelope's home module
- agent-section ModelsBody.slots type honest to the nullable contract

components/settings/agent-section.tsx

@@ -85,9 +85,10 @@ interface SegmentInfo {
 /** The GET /api/models response fields this section consumes. */
 interface ModelsBody {
 	models: ModelCatalogEntry[];
-	/** The three tiers' RESOLVED pins (override → factory) — the honest
-	 *  "what runs now" the Default rows and hints speak from. */
-	slots: Record<ModelSlotName, { model: { provider: string; id: string }; thinkingLevel?: string }>;
+	/** The three tiers' RESOLVED pins (BYOK: NULL per unset tier — no
+	 *  factory floor) — machinery only (the thinking list fallback); the
+	 *  rows' displays read the record override, never a phantom pin. */
+	slots: Record<ModelSlotName, { model: { provider: string; id: string }; thinkingLevel?: string } | null>;
 }
 
 /** Compose: one tool toggled, the rest of the section carried verbatim.