Phase 1b: React Query + Vitest on client

- @tanstack/react-query v5 with QueryClientProvider at app root
- client/src/api/queries.ts: query-key factory, hooks for tickets, ticket, audit,
  comments, users, CTI tree + cascade, plus full mutation set
  (create/update/delete ticket, add/delete comment, CTI CRUD, user CRUD)
- All page-level useEffect + useState fetching replaced:
  Dashboard, MyTickets, TicketDetail, NewTicket, admin/CTI, admin/Users
- Dashboard preserves 300ms debounced search via separate debouncedSearch state
- CTISelect cascades via useCategories / useTypes(categoryId) / useItems(typeId);
  dependent hooks disabled until parent selected
- vitest + @testing-library/react + jsdom; 6 client tests cover SeverityBadge + StatusBadge

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

client/src/components/CTISelect.tsx

@@ -1,6 +1,4 @@
-import { useEffect, useState } from 'react';
-import api from '../api/client';
-import { Category, CTIType, Item } from '../types';
+import { useCategories, useItems, useTypes } from '../api/queries';
 
 interface CTISelectProps {
   value: { categoryId: string; typeId: string; itemId: string };
@@ -9,34 +7,9 @@ interface CTISelectProps {
 }
 
 export default function CTISelect({ value, onChange, disabled }: CTISelectProps) {
-  const [categories, setCategories] = useState<Category[]>([]);
-  const [types, setTypes] = useState<CTIType[]>([]);
-  const [items, setItems] = useState<Item[]>([]);
-
-  useEffect(() => {
-    api.get<Category[]>('/cti/categories').then((r) => setCategories(r.data));
-  }, []);
-
-  useEffect(() => {
-    if (!value.categoryId) {
-      setTypes([]);
-      setItems([]);
-      return;
-    }
-    api
-      .get<CTIType[]>('/cti/types', { params: { categoryId: value.categoryId } })
-      .then((r) => setTypes(r.data));
-  }, [value.categoryId]);
-
-  useEffect(() => {
-    if (!value.typeId) {
-      setItems([]);
-      return;
-    }
-    api
-      .get<Item[]>('/cti/items', { params: { typeId: value.typeId } })
-      .then((r) => setItems(r.data));
-  }, [value.typeId]);
+  const { data: categories = [] } = useCategories();
+  const { data: types = [] } = useTypes(value.categoryId || undefined);
+  const { data: items = [] } = useItems(value.typeId || undefined);
 
   const handleCategory = (categoryId: string) => {
     onChange({ categoryId, typeId: '', itemId: '' });