fix: vision slot filters to image-capable + custom models (was relaxing for all providers)

The prior change made the vision slot show every model (image-capable first),
which relaxed the filter for built-in providers too — built-in text-only models
became selectable for Vision. Centralize the vision rule in ModelMenuList:
built-ins must report image input; custom-endpoint models stay selectable (their
capability may be unreported). Image-capable still float first.

components/settings/model-menu.tsx

@@ -21,7 +21,7 @@
 
 import { useEffect, useRef, useState } from "react";
 import type { ModelCatalogEntry } from "@/src/core";
-import { fuzzyScore, subscriptionLabel } from "@/src/core";
+import { CUSTOM_PROVIDER, fuzzyScore, subscriptionLabel } from "@/src/core";
 import { formatTokens } from "@/components/usage-format";
 import { SearchMenuList } from "./search-menu-list";
 
@@ -39,7 +39,7 @@ export function ModelMenuList({
 	effectiveProvider,
 	onPick,
 	footer,
-	prioritizeImage,
+	vision,
 }: {
 	/** The full catalog — undefined while it loads. */
 	models: ModelCatalogEntry[] | undefined;
@@ -54,19 +54,25 @@ export function ModelMenuList({
 	onPick: (entry: ModelCatalogEntry) => void;
 	/** Quiet footer note under the list (context-specific). */
 	footer?: string;
-	/** Vision slot: image-capable models float to the top (still all
-	 *  selectable — a custom endpoint that doesn't report modality must
-	 *  stay pickable, so this orders rather than filters). */
-	prioritizeImage?: boolean;
+	/** Vision slot: only image-capable models are selectable — plus every
+	 *  custom-endpoint model, whose capability the endpoint may not report.
+	 *  Image-capable ones float to the top. */
+	vision?: boolean;
 }) {
+	// Vision slot: built-ins must report image input; custom-endpoint models
+	// stay selectable (the endpoint may not report a modality). Image-capable
+	// ones float to the top of the list.
+	const visionItems = vision
+		? models?.filter((m) => m.input.includes("image") || m.provider === CUSTOM_PROVIDER.id)
+		: models;
 	return (
 		<>
 			<SearchMenuList
-				items={models}
+				items={visionItems}
 				itemKey={(m) => `${m.provider}/${m.id}`}
 				searchTerms={(m) => [m.provider, m.id, m.name]}
 				compare={(a, b) => a.id.localeCompare(b.id)}
-				prioritize={prioritizeImage ? (m) => m.input.includes("image") : undefined}
+				prioritize={vision ? (m) => m.input.includes("image") : undefined}
 				isSelected={(m) => m.id === effectiveId && m.provider === (effectiveProvider ?? m.provider)}
 				onPick={onPick}
 				searchTestid="model-search"