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>

CHANGELOG.md

@@ -4,6 +4,16 @@ All notable changes to this project will be documented in this file.
 
 ## [Unreleased]
 
+### Fixed (Safe Formatting Utilities — 2026-02-15)
+
+**Frontend:**
+- `AnalyticsView.vue` — Replaced unsafe `.toFixed()` calls with `safeFixed()` for avg_players and uptime_percentage (2 occurrences)
+- `WipeAnalyticsView.vue` — Replaced unsafe `.toFixed()` calls with `safeFixed()` for all metrics properties: success_rate_percent, population_curve stats, wipe durations, and CSV export (5 occurrences)
+- `PlayerRetentionView.vue` — Replaced unsafe `.toFixed()` calls with `safeFixed()` for retention percentages and session durations (5 occurrences in template + 1 in tooltip formatter)
+- `MapAnalyticsView.vue` — Replaced unsafe `.toFixed()` calls with `safeFixed()` for rotation effectiveness, map performance metrics, and table display (6 occurrences)
+
+**Purpose:** Prevents runtime errors from calling `.toFixed()` on null/undefined values in analytics views. Uses the safe formatting utilities from `@/utils/formatters.ts` with optional chaining for all numeric display operations.
+
 ### Fixed (NestJS Entity Alignment — 2026-02-15)
 
 **Backend (NestJS):**