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>

packages/db/src/schema/users.ts

@@ -208,6 +208,7 @@ export const userFeaturePrefs = pgTable("user_feature_prefs", {
   shoppingLists: boolean("shopping_lists").notNull().default(true),
   collections: boolean("collections").notNull().default(true),
   messages: boolean("messages").notNull().default(true),
+  chatbots: boolean("chatbots").notNull().default(true),
   updatedAt: timestamp("updated_at").notNull().defaultNow(),
 });