Refactor useToast hook into modules

The useToast hook was refactored into smaller, more manageable modules.

src/hooks/toast/store.ts

@@ -3,7 +3,6 @@ import { State } from './types'
 
 // 전역 상태 및 리스너
 export const listeners: Array<(state: State) => void> = []
-export let memoryState: State = { toasts: [] }
 
-// 마지막 액션 추적 (중복 방지용)
-export let lastAction: { type: string; id?: string; time: number } | null = null
+// memoryState와 lastAction은 toastManager.ts에서 관리
+export { memoryState } from './toastManager';