Refactor StoreKit 2 subscription system and add interactive vote widget

## StoreKit 2 Refactor
- Rewrote IAPManager with clean enum-based state model (SubscriptionState)
- Added native SubscriptionStoreView for iOS 17+ purchase UI
- Subscription status now checked on every app launch
- Synced subscription status to UserDefaults for widget access
- Simplified PurchaseButtonView and IAPWarningView
- Removed unused StatusInfoView

## Interactive Vote Widget
- New FeelsVoteWidget with App Intents for mood voting
- Subscribers can vote directly from widget, shows stats after voting
- Non-subscribers see "Tap to subscribe" which opens subscription store
- Added feels:// URL scheme for deep linking

## Firebase Removal
- Commented out Firebase imports and initialization
- EventLogger now prints to console in DEBUG mode only

## Other Changes
- Added fallback for Core Data when App Group unavailable
- Added new localization strings for subscription UI
- Updated entitlements and Info.plist

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

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

Shared/AppDelegate.swift

@@ -10,7 +10,7 @@ import UserNotifications
 import UIKit
 import WidgetKit
 import SwiftUI
-import Firebase
+// import Firebase  // Firebase removed
 
 class AppDelegate: NSObject, UIApplicationDelegate {
     private let savedOnboardingData = UserDefaultsStore.getOnboarding()
@@ -22,7 +22,7 @@ class AppDelegate: NSObject, UIApplicationDelegate {
 //                PersistenceController.shared.deleteRandomFromLast(numberOfEntries: 10)
         //        GroupUserDefaults.groupDefaults.set(false, forKey: UserDefaultsStore.Keys.showNSFW.rawValue)
         
-        FirebaseApp.configure()
+        // FirebaseApp.configure()  // Firebase removed
         PersistenceController.shared.removeNoForDates()
         PersistenceController.shared.fillInMissingDates()
         UNUserNotificationCenter.current().delegate = self