chore: upgrade tooling stack

- TypeScript 3.9 -> 5.8
- ESLint 6 -> 9 (flat config)
- Prettier 1 -> 3
- eslint-plugin-vue 6 -> 9
- Add vue-tsc for type checking
- Migrate Sass @import to @use syntax
- Fix Pinia persistence config for v4
- Add Spotify type declarations
- Remove unused registerServiceWorker.ts

src/hooks/useTimer.ts

@@ -33,8 +33,8 @@ export const useTimer = () => {
   const session = computed(() => formatSeconds(sessionSeconds.value))
   const intervalSeconds = computed(() => interval.value * 60)
 
-  let stopwatchId: NodeJS.Timeout | null = null
-  let stopWatchSessionId: NodeJS.Timeout | null = null
+  let stopwatchId: ReturnType<typeof setInterval> | null = null
+  let stopWatchSessionId: ReturnType<typeof setInterval> | null = null
 
   watch(interval, () => {
     sessionSeconds.value = interval.value * 60
@@ -55,8 +55,8 @@ export const useTimer = () => {
 
         toggleSound.play()
 
-        notify(i18n.t('notification.change.title').toString(), {
-          body: i18n.t('notification.change.body', { dev }).toString()
+        notify(i18n.global.t('notification.change.title'), {
+          body: i18n.global.t('notification.change.body', { dev })
         })
       }
     }, 1000)