Enhance TrainingCoachPage and trainingPlanUtils with session storage management and phase handling improvements

- Introduced a new function in TrainingCoachPage to clear session storage for coach steps, improving state management during training sessions.
- Updated the sectionsWithPlanLocForDisplay function in trainingPlanUtils to include logic for determining the maximum phase order index, enhancing phase handling.
- Enhanced the mapping of sections to include default plan locations for parallel phases, optimizing data representation and user experience.

frontend/src/pages/TrainingCoachPage.jsx

@@ -27,6 +27,18 @@ function storageStepKey(unitId, mergedPicks) {
   return `sj_coach_step_${unitId}_${coachBranchPicksStepStorageSuffix(mergedPicks)}`
 }
 
+function clearCoachStepStorageForUnit(unitId) {
+  const pref = `sj_coach_step_${unitId}_`
+  try {
+    for (let i = sessionStorage.length - 1; i >= 0; i -= 1) {
+      const k = sessionStorage.key(i)
+      if (k && k.startsWith(pref)) sessionStorage.removeItem(k)
+    }
+  } catch {
+    /* ignore */
+  }
+}
+
 function storageDeltasKey(unitId) {
   return `sj_coach_deltas_${unitId}`
 }
@@ -614,9 +626,12 @@ export default function TrainingCoachPage() {
         sessionStorage.removeItem(storageDeltasKey(idNum))
         sessionStorage.removeItem(storageDebriefKey(idNum))
         sessionStorage.removeItem(coachBranchPicksStorageKey(idNum))
+        clearCoachStepStorageForUnit(idNum)
       } catch {
         /* ignore */
       }
+      setSearchParams({}, { replace: true })
+      setStep(0)
       setDeltas({})
       setBranchPicks({})
       setStreamChoiceHint(null)

frontend/src/utils/trainingPlanUtils.js

@@ -5,6 +5,7 @@
 import {
   buildPlanPayloadForSave,
   cloneJsonSerializablePlanningProfile,
+  defaultPlanLocWholeGroup,
   inheritPlanLocForPhasedSave,
   phaseRunsFromSections,
   sectionIndicesForParallelStream,
@@ -94,6 +95,16 @@ function planLocBySectionIdFromPhases(phases) {
   return byId
 }
 
+function maxPhaseOrderIndexFromNestedPhases(phases) {
+  let m = -1
+  if (!Array.isArray(phases)) return m
+  for (const ph of phases) {
+    const po = Number(ph.order_index ?? ph.orderIndex ?? 0)
+    if (Number.isFinite(po)) m = Math.max(m, po)
+  }
+  return m
+}
+
 export function sectionsWithPlanLocForDisplay(unit) {
   const sorted = sortedSections(unit)
   const byId = planLocBySectionIdFromPhases(unit?.phases)
@@ -105,7 +116,25 @@ export function sectionsWithPlanLocForDisplay(unit) {
     if (s.planLoc && s.planLoc.phaseKind) return s
     return { ...s }
   })
-  return inheritPlanLocForPhasedSave(merged)
+  const inherited = inheritPlanLocForPhasedSave(merged)
+  const maxPhPo = maxPhaseOrderIndexFromNestedPhases(unit?.phases)
+  return inherited.map((s) => {
+    const sid = s.id != null ? Number(s.id) : NaN
+    if (!Number.isFinite(sid) || byId.has(sid)) return s
+    const pl = s.planLoc
+    if (pl?.phaseKind === 'parallel') {
+      const po = maxPhPo >= 0 ? maxPhPo + 1 : 0
+      return {
+        ...s,
+        planLoc: {
+          ...defaultPlanLocWholeGroup(po),
+          phaseTitle: pl.phaseTitle ?? null,
+          phaseGuidanceNotes: pl.phaseGuidanceNotes ?? null,
+        },
+      }
+    }
+    return s
+  })
 }
 
 /**