Add native iOS in-app review request system

Implement ReviewRequestManager using StoreKit's SKStoreReviewController
to request reviews at moments of user delight:
- Streak milestones (3, 7, 14, 30, 50, 100 days)
- Every 10th mood entry after minimum usage threshold

Includes frequency limiting (60+ days between requests, minimum 5 entries
before first prompt) and tracks request history via UserDefaults.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Shared/MoodLogger.swift

@@ -61,7 +61,10 @@ final class MoodLogger {
             TipsManager.shared.updateStreak(streak)
         }
 
-        // 6. Reload widgets
+        // 6. Request app review at moments of delight
+        ReviewRequestManager.shared.onMoodLogged(streak: streak)
+
+        // 7. Reload widgets
         WidgetCenter.shared.reloadAllTimelines()
     }