memoize t in the typed wrappers, and give app code typed access to ui.*

Each wrapper built a fresh closure every render, so `t` in a dependency array
recomputed forever. That is the documented useClient()/Jellyfin trap in
platform/CLAUDE.md, and phase 2 needs t in useMemo deps immediately.

useTranslation in officer-web now also returns tUi, typed against the shared
components' catalog. 'Cancel' and 'Close' recur across the shell and already exist
in ui.* — the alternative was importing two hooks in a hundred files.

src/workspaces/components/locales/useTranslation.ts

@@ -1,4 +1,5 @@
 import type { InterpolationParams, TranslationKeys } from 'i18n';
+import { useCallback } from 'react';
 import { useTranslation as useTranslationBase } from 'i18n';
 import type en from './en-GB.json';
 
@@ -8,6 +9,8 @@ type UiTranslationKey = TranslationKeys<typeof en>;
 // pass the same bare key the JSON file uses. `ui.*` may not name a feature (see the naming convention).
 export const useTranslation = () => {
   const { t: baseT, locale } = useTranslationBase();
-  const t = (key: UiTranslationKey, params?: InterpolationParams) => baseT(`ui.${key}`, params);
+  // Memoized: an unstable `t` is unusable in a dependency array. See platform/CLAUDE.md on the
+  // `useClient()` trap that silently disabled the Jellyfin player's playback reports.
+  const t = useCallback((key: UiTranslationKey, params?: InterpolationParams) => baseT(`ui.${key}`, params), [baseT]);
   return { t, locale };
 };

src/workspaces/officerdev/src/locales/useTranslation.ts

@@ -1,4 +1,5 @@
 import type { InterpolationParams, TranslationKeys } from 'i18n';
+import { useCallback } from 'react';
 import { useTranslation as useTranslationBase } from 'i18n';
 import type en from './en-GB.json';
 
@@ -8,6 +9,11 @@ type PanelTranslationKey = TranslationKeys<typeof en>;
 // pass the same bare key the JSON file uses.
 export const useTranslation = () => {
   const { t: baseT, locale } = useTranslationBase();
-  const t = (key: PanelTranslationKey, params?: InterpolationParams) => baseT(`panel.${key}`, params);
+  // Memoized: an unstable `t` is unusable in a dependency array. See platform/CLAUDE.md on the
+  // `useClient()` trap that silently disabled the Jellyfin player's playback reports.
+  const t = useCallback(
+    (key: PanelTranslationKey, params?: InterpolationParams) => baseT(`panel.${key}`, params),
+    [baseT],
+  );
   return { t, locale };
 };