Fix schedule blocks persisting after End Day without refresh

Clear blocks, completedBlockIds, and day times alongside session when
the is_active: false WS event is received.

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

frontend/src/stores/schedule.js

@@ -51,9 +51,13 @@ export const useScheduleStore = defineStore('schedule', () => {
     // Session ended
     if (event.is_active === false) {
       session.value = null
+      blocks.value = []
+      completedBlockIds.value = []
       isPaused.value = false
       blockStartedAt.value = null
       blockElapsedOffset.value = 0
+      dayStartTime.value = null
+      dayEndTime.value = null
       return
     }
     // Pause — accumulate elapsed, stop counting