fix: desktop nav ignored feature toggles; add chatbots toggle (v0.62.0)

Feature toggles (Settings -> Features) were filtered into
visibleNavItems but the desktop horizontal nav still mapped over the
raw NAV_ITEMS list, so hiding a feature only worked on mobile. Both
nav renders now read the same filtered list.

Also adds a Chatbots toggle covering the recipe cooking-chat panel
and the recipe-list cooking assistant, wired end-to-end (schema,
migration, feature-prefs lib, API route, settings form, i18n,
openapi).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/web/app/api/v1/users/me/feature-prefs/route.ts

@@ -11,6 +11,7 @@ const PutSchema = z.object({
   shoppingLists: z.boolean().optional(),
   collections: z.boolean().optional(),
   messages: z.boolean().optional(),
+  chatbots: z.boolean().optional(),
 });
 
 export async function GET() {