Replace EventLogger with typed AnalyticsManager using PostHog

Complete analytics overhaul: delete EventLogger.swift, create Analytics.swift
with typed event enum (~45 events), screen tracking, super properties
(theme, icon pack, voting layout, etc.), session replay with kill switch,
autocapture, and network telemetry. Replace all 99 call sites across 38 files
with compiler-enforced typed events in object_action naming convention.

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

Shared/Models/AppTheme.swift

@@ -266,7 +266,9 @@ enum AppTheme: Int, CaseIterable, Identifiable {
         GroupUserDefaults.groupDefaults.set(lockScreenStyle.rawValue, forKey: UserDefaultsStore.Keys.lockScreenStyle.rawValue)
 
         // Log the theme change
-        EventLogger.log(event: "apply_theme", withData: ["theme": name])
+        Task { @MainActor in
+            AnalyticsManager.shared.track(.themeApplied(themeName: name))
+        }
     }
 }