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/admin/WipesView.vue

@@ -4,6 +4,7 @@ import { useWipeStore } from '@/stores/wipe'
 import { useServerStore } from '@/stores/server'
 import { RefreshCw, Zap, Clock, AlertTriangle, Loader2 } from 'lucide-vue-next'
 import { RouterLink } from 'vue-router'
+import { safeDate } from '@/utils/formatters'
 
 const wipeStore = useWipeStore()
 const server = useServerStore()
@@ -160,7 +161,7 @@ onMounted(() => {
         >
           <div>
             <p class="text-sm text-neutral-200">{{ wipe.wipe_type }} wipe</p>
-            <p class="text-xs text-neutral-500">{{ wipe.trigger_type }} &middot; {{ wipe.started_at ? new Date(wipe.started_at).toLocaleString() : 'Pending' }}</p>
+            <p class="text-xs text-neutral-500">{{ wipe.trigger_type }} &middot; {{ safeDate(wipe.started_at, 'Pending') }}</p>
           </div>
           <span
             class="text-xs font-medium px-2 py-0.5 rounded-full"