fix: Replace unsafe .toFixed() calls with safeFixed() in analytics views

- AnalyticsView: avg_players, uptime_percentage
- WipeAnalyticsView: success_rate, population curve, durations, CSV export
- PlayerRetentionView: retention percentages, session duration, tooltip
- MapAnalyticsView: rotation effectiveness, performance metrics, table

All analytics views now use safe formatter utilities with optional chaining
to prevent null/undefined runtime errors when displaying numeric data.

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

frontend/src/views/public/StoreView.vue

@@ -3,6 +3,7 @@ import { ref, computed, onMounted } from 'vue'
 import { useRoute } from 'vue-router'
 import type { PublicStoreInfo, PublicStoreItem, StorePurchaseRequest, StorePurchaseResponse } from '@/types'
 import { ShoppingCart, Package, Filter, X, AlertCircle, ExternalLink, Check } from 'lucide-vue-next'
+import { safeCurrency } from '@/utils/formatters'
 
 const route = useRoute()
 const subdomain = computed(() => route.params.subdomain as string)
@@ -138,7 +139,7 @@ async function confirmPurchase() {
 }
 
 function formatPrice(price: number): string {
-  return `$${price.toFixed(2)}`
+  return safeCurrency(price, '$')
 }
 
 function itemTypeBadgeClass(itemType: string): string {