fix: correct ESLint fixes to use Zustand getState() pattern

The previous fix created unstable dependencies by using the entire
store state object in useEffect dependencies, causing re-renders
and test timeouts.

Changes:
- app/[locale]/page.tsx: Use useTimerStore.getState().tick() to avoid
  tick function dependency issues
- ServiceWorkerRegistration.tsx: Use useNotificationStore.getState()
  to avoid setPermission dependency issues
- Remove unused useStore import

This follows Zustand best practices for accessing actions in effects
without creating dependencies on store state.

Verified locally:
- pnpm lint: passes with --max-warnings=0
- pnpm build: successful production build

Author: ryota-murakami

app/[locale]/page.tsx

@@ -57,14 +57,15 @@ export default function Home() {
 
   // Set up interval for ticking when timer is running
   useEffect(() => {
-    if (!isRunning || !timerState?.tick) return
+    if (!isRunning) return
 
     const interval = setInterval(() => {
-      timerState.tick()
+      // Call tick from the store directly to avoid dependency issues
+      useTimerStore.getState().tick()
     }, 1000)
 
     return () => clearInterval(interval)
-  }, [isRunning, timerState])
+  }, [isRunning])
 
   // Play sound and show notification when timer completes
   useEffect(() => {

components/notifications/ServiceWorkerRegistration.tsx

@@ -2,7 +2,6 @@
 
 import { useEffect } from 'react'
 import { useNotificationStore } from '@/lib/stores/notificationStore'
-import useStore from '@/lib/hooks/useStore'
 import {
   registerServiceWorker,
   getNotificationPermission,
@@ -13,11 +12,7 @@ import {
  * Registers the Service Worker on app load and syncs notification permission state
  */
 export function ServiceWorkerRegistration() {
-  const notificationStore = useStore(useNotificationStore, (state) => state)
-
   useEffect(() => {
-    const setPermission = notificationStore?.setPermission ?? (() => {})
-    
     // Register Service Worker
     registerServiceWorker().then((registration) => {
       if (registration) {
@@ -27,22 +22,22 @@ export function ServiceWorkerRegistration() {
 
     // Sync initial permission state
     const permission = getNotificationPermission()
-    setPermission(permission)
+    useNotificationStore.getState().setPermission(permission)
 
     // Listen for permission changes (some browsers support this)
     if ('permissions' in navigator) {
       navigator.permissions
         .query({ name: 'notifications' as PermissionName })
         .then((permissionStatus) => {
           permissionStatus.addEventListener('change', () => {
-            setPermission(getNotificationPermission())
+            useNotificationStore.getState().setPermission(getNotificationPermission())
           })
         })
         .catch((error) => {
           console.warn('[Notifications] Permission monitoring not supported:', error)
         })
     }
-  }, [notificationStore])
+  }, [])
 
   // This component doesn't render anything
   return null