fix: resolve all 15 frontend ESLint errors for green CI

- Replace setState-in-effect with state-based tracking (AdminLayout, EditCategoryModal)
- Convert inline SortIcon component to getSortIcon function (TreeTableView)
- Remove unused catch parameters (CreateCategoryModal, EditCategoryModal)
- Replace `any` types with proper types (SessionFilters, AdminCategoriesPage, SessionHistoryPage)
- Fix unused destructuring variable (StepRatingModal)
- Fix constant binary expression in test (utils.test.ts)

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

frontend/src/pages/AdminCategoriesPage.tsx

@@ -13,7 +13,7 @@ import { toast } from '@/lib/toast'
 
 export function AdminCategoriesPage() {
   const [categories, setCategories] = useState<StepCategoryListItem[]>([])
-  const [allSteps, setAllSteps] = useState<any[]>([])
+  const [allSteps, setAllSteps] = useState<{ category_id?: string }[]>([])
   const [isLoading, setIsLoading] = useState(true)
   const [showCreateModal, setShowCreateModal] = useState(false)
   const [showEditModal, setShowEditModal] = useState(false)

frontend/src/pages/SessionHistoryPage.tsx

@@ -75,7 +75,7 @@ export function SessionHistoryPage() {
   const loadSessions = async () => {
     setIsLoading(true)
     try {
-      const params: any = {}
+      const params: Record<string, string | boolean> = {}
 
       // Tab filter (all/active/completed)
       if (filter !== 'all') {