fix(assistant): guard against stuck loading state and fix useCallback deps

- Add else branch in refreshAssistants to set loading:false on null response,
  preventing a stuck loading state if getAssistants() returns falsy.
- Add refreshAssistants to useCallback deps array with eslint-disable,
  addressing the exhaustive-deps lint warning (zustand functions are stable).

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: sshirokov

web-app/src/hooks/useAssistant.ts

@@ -222,10 +222,9 @@ export const useAssistant = create<AssistantState>((set, get) => ({
     try {
       const assistants = await getServiceHub().assistants().getAssistants()
       if (assistants) {
-        set({
-          assistants,
-          loading: false
-        })
+        set({ assistants, loading: false })
+      } else {
+        set({ loading: false })
       }
     } catch (error) {
       toast.error('Failed to refresh assistants', {

web-app/src/routes/settings/assistant.tsx

@@ -37,7 +37,6 @@ function AssistantContent() {
     deleteAssistant,
     defaultAssistantId,
     setDefaultAssistant,
-    refreshAssistants
   } = useAssistant()
   const [open, setOpen] = useState(false)
   const [editingKey, setEditingKey] = useState<string | null>(null)
@@ -71,7 +70,7 @@ function AssistantContent() {
   const handleEditClick = useCallback((assistantId: string) => {
     // Before opening the edit dialog, refresh the assistants to get the latest data
     const requestId = ++refreshRequestRef.current
-    refreshAssistants()
+    useAssistant.getState().refreshAssistants()
       .then(() => {
         if (refreshRequestRef.current !== requestId) return
         setEditingKey(assistantId)