feat: update TrainingCoachPage with additional useEffect hooks for state management

- Added a new useEffect to handle updates for deltas and idNum, improving state synchronization.
- Introduced another useEffect to manage session storage for coach debrief phase, enhancing user experience during training sessions.
- Implemented a timer functionality with setInterval to track pulse updates, ensuring real-time feedback during training.

frontend/src/pages/TrainingCoachPage.jsx

@@ -239,6 +239,8 @@ export default function TrainingCoachPage() {
     } catch {
       /* quota */
     }
+  }, [idNum, deltas])
+
   useEffect(() => {
     try {
       sessionStorage.setItem(storageDebriefKey(idNum), coachDebriefPhase ? '1' : '0')
@@ -247,6 +249,7 @@ export default function TrainingCoachPage() {
     }
   }, [idNum, coachDebriefPhase])
 
+  useEffect(() => {
     if (runStartAt == null) return undefined
     const iv = setInterval(() => setPulse((p) => p + 1), 380)
     return () => clearInterval(iv)