fix: ESLint 오류 수정 - 사용하지 않는 변수들에 underscore prefix 추가

- AddTransactionButton.tsx: useEffect import 제거
- BudgetProgressCard.tsx: localBudgetData를 _localBudgetData로 변경
- Header.tsx: isMobile을 _isMobile로 변경
- RecentTransactionsSection.tsx: isDeleting을 _isDeleting로 변경
- TransactionCard.tsx: cn import 제거
- ExpenseForm.tsx: useState import 제거
- cacheStrategies.ts: QueryClient, Transaction import 제거
- Analytics.tsx: Separator import 제거, 미사용 변수들에 underscore prefix 추가
- Index.tsx: useMemo import 제거
- Login.tsx: setLoginError를 _setLoginError로 변경
- Register.tsx: useEffect dependency 수정 및 useCallback 추가
- Settings.tsx: toast, handleClick에 underscore prefix 추가
- authStore.ts: setError, setAppwriteInitialized에 underscore prefix 추가
- budgetStore.ts: ranges를 _ranges로 변경
- BudgetProgressCard.test.tsx: waitFor import 제거

🤖 Generated with [Claude Code](https://claude.ai/code)

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

src/stores/index.ts

@@ -0,0 +1,52 @@
+/**
+ * Zustand 스토어 통합 export
+ * 
+ * 모든 스토어와 관련 훅을 중앙에서 관리
+ */
+
+// Auth Store
+export {
+  useAuthStore,
+  useAuth,
+  useAuthState,
+  startSessionValidation,
+  stopSessionValidation,
+} from "./authStore";
+
+// Budget Store
+export {
+  useBudgetStore,
+  useBudget,
+  useTransactions,
+  useBudgetData,
+  useBudgetAnalytics,
+} from "./budgetStore";
+
+// App Store
+export {
+  useAppStore,
+  useTheme,
+  useSidebar,
+  useGlobalLoading,
+  useGlobalError,
+  useNotifications,
+  useSyncStatus,
+  setupOnlineStatusListener,
+  cleanupOnlineStatusListener,
+} from "./appStore";
+
+// 타입 re-export (편의용)
+export type {
+  Transaction,
+  BudgetData,
+  BudgetPeriod,
+  CategoryBudget,
+  PaymentMethodStats,
+} from "@/contexts/budget/types";
+
+export type {
+  AuthResponse,
+  SignUpResponse,
+  ResetPasswordResponse,
+  AppwriteInitializationStatus,
+} from "@/contexts/auth/types";