feat(web): vocabularies two-pane screen (list/create + terms/add) + nav

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

web/src/shell/app-shell.tsx

@@ -5,7 +5,7 @@ import { useLogout } from "../api/queries";
 import { Button } from "@/components/ui/button";
 import { LangSwitch } from "./lang-switch";
 
-const FUTURE = ["vocabularies", "authorities", "fields", "search"] as const;
+const DISABLED_NAV = ["authorities", "fields", "search"] as const;
 
 export function AppShell() {
   const { t } = useTranslation();
@@ -30,7 +30,15 @@ export function AppShell() {
           >
             {t("nav.objects")}
           </NavLink>
-          {FUTURE.map((key) => (
+          <NavLink
+            to="/vocabularies"
+            className={({ isActive }) =>
+              `block rounded px-2 py-1 ${isActive ? "bg-neutral-200 font-medium" : ""}`
+            }
+          >
+            {t("nav.vocabularies")}
+          </NavLink>
+          {DISABLED_NAV.map((key) => (
             <button
               key={key}
               disabled