Add payoff amount, fix dialog overlay and nav highlight for sub-routes

- Show estimated payoff amount (balance + accrued interest) in loan summary
- Display loan balances as absolute values in red
- Fix dialog overlay blocking UI after edit by closing in finally with nextTick
- Highlight parent nav item when viewing sub-routes (e.g. /loans/:id)

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

frontend/src/components/layout/AppLayout.vue

@@ -159,6 +159,8 @@ const navItems = [
 
 function isNavActive(navRoute: string) {
   if (route.path === navRoute) return true
+  // Highlight parent nav for sub-routes (e.g. /loans/:id highlights Loans)
+  if (navRoute !== '/' && route.path.startsWith(navRoute + '/')) return true
   // Highlight "Transactions" when viewing account-scoped transactions
   if (navRoute === '/transactions' && route.name === 'account-transactions') return true
   return false

frontend/src/views/loans/LoansView.vue

@@ -18,7 +18,7 @@
             <v-card-text>
               <div class="d-flex justify-space-between mb-1">
                 <span class="text-medium-emphasis">Balance</span>
-                <span class="font-weight-bold">{{ formatCurrency(account.balance) }}</span>
+                <span class="font-weight-bold text-red">{{ formatCurrency(Math.abs(account.balance)) }}</span>
               </div>
               <div v-if="account.interestRate" class="d-flex justify-space-between mb-1">
                 <span class="text-medium-emphasis">Interest Rate</span>
@@ -69,7 +69,11 @@
             </v-col>
             <v-col cols="6" md="3">
               <div class="text-medium-emphasis text-caption">Current Balance</div>
-              <div class="text-h6">{{ formatCurrency(loanDetail.currentBalance) }}</div>
+              <div class="text-h6 text-red">{{ formatCurrency(Math.abs(loanDetail.currentBalance)) }}</div>
+            </v-col>
+            <v-col v-if="payoffAmount != null" cols="6" md="3">
+              <div class="text-medium-emphasis text-caption">Est. Payoff Amount</div>
+              <div class="text-h6 text-red">{{ formatCurrency(payoffAmount) }}</div>
             </v-col>
             <v-col cols="6" md="3">
               <div class="text-medium-emphasis text-caption">Interest Rate</div>
@@ -250,7 +254,7 @@
 </template>
 
 <script setup lang="ts">
-import { ref, computed, onMounted, watch } from 'vue'
+import { ref, computed, nextTick, onMounted, watch } from 'vue'
 import { useRouter } from 'vue-router'
 import { loansApi } from '@/services/loans'
 import { useAccountsStore } from '@/stores/accounts'
@@ -287,6 +291,30 @@ const filteredSchedule = computed(() => {
   return loanDetail.value.amortizationSchedule.filter(e => e.paymentDate.split('T')[0] >= today)
 })
 
+const dailyAccrualTypes = ['AutoLoan', 'LineOfCredit']
+const payoffAmount = computed(() => {
+  if (!loanDetail.value || !props.id) return null
+  const balance = Math.abs(loanDetail.value.currentBalance)
+  if (balance === 0) return 0
+  const account = accountsStore.accounts.find(a => a.id === props.id)
+  if (!account) return balance
+  const rate = loanDetail.value.interestRate / 100
+  const today = new Date()
+  const todayStr = today.toISOString().split('T')[0]
+  const schedule = loanDetail.value.amortizationSchedule
+  const lastPast = [...schedule].reverse().find(e => e.paymentDate.split('T')[0] <= todayStr)
+  if (!lastPast) return balance
+  const lastDate = new Date(lastPast.paymentDate.split('T')[0] + 'T00:00:00')
+  const todayMidnight = new Date(todayStr + 'T00:00:00')
+  const days = Math.round((todayMidnight.getTime() - lastDate.getTime()) / 86400000)
+  if (days <= 0) return balance
+  const isDailyAccrual = dailyAccrualTypes.includes(account.type)
+  const accruedInterest = isDailyAccrual
+    ? balance * rate / 365 * days
+    : balance * rate / 12 * (days / 30)
+  return balance + accruedInterest
+})
+
 const amortHeaders = [
   { title: '#', key: 'paymentNumber', width: '60px' },
   { title: 'Date', key: 'paymentDate', width: '110px' },
@@ -404,12 +432,13 @@ async function saveLoanDetail() {
       await loansApi.createLoanDetail(props.id, payload)
       showSnackbar('Loan details created')
     }
-    showLoanDialog.value = false
-    await loadLoanDetail()
   } catch {
     showSnackbar('Failed to save loan details', 'error')
   } finally {
     saving.value = false
+    showLoanDialog.value = false
+    await nextTick()
+    await loadLoanDetail()
   }
 }