Fix build errors, resolve all warnings, and improve code quality

Widget Extension Fixes:
- Create standalone WidgetDataProvider for widget data isolation
- Add WIDGET_EXTENSION compiler flag for conditional compilation
- Fix DataController references in widget-shared files
- Sync widget version numbers with main app (23, 1.0.2)
- Add WidgetBackground color to asset catalog

Warning Resolutions:
- Fix UIScreen.main deprecation in BGView and SharingListView
- Fix Text '+' concatenation deprecation in PurchaseButtonView and SettingsTabView
- Fix exhaustive switch in BiometricAuthManager (add .none case)
- Fix var to let in ExportService (3 instances)
- Fix unused result warning in NoteEditorView
- Fix ForEach duplicate ID warnings in MonthView and YearView

Code Quality Improvements:
- Wrap bypassSubscription in #if DEBUG for security
- Rename StupidAssCustomWidgetObservableObject to CustomWidgetStateViewModel
- Add @MainActor to IconViewModel
- Replace fatalError with graceful fallback in SharedModelContainer
- Add [weak self] to closures in DayViewViewModel
- Add OSLog-based AppLogger for production logging
- Add ImageCache with NSCache for memory efficiency
- Add AccessibilityHelpers with Reduce Motion support
- Create DataControllerProtocol for dependency injection
- Update .gitignore with secrets exclusions

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

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

Shared/IAPManager.swift

@@ -8,6 +8,7 @@
 import Foundation
 import StoreKit
 import SwiftUI
+import os.log
 
 // MARK: - Subscription State
 
@@ -27,7 +28,11 @@ class IAPManager: ObservableObject {
     // MARK: - Debug Toggle
 
     /// Set to `true` to bypass all subscription checks and grant full access (for development only)
+    #if DEBUG
     static let bypassSubscription = true
+    #else
+    static let bypassSubscription = false
+    #endif
 
     // MARK: - Constants
 
@@ -151,7 +156,7 @@ class IAPManager: ObservableObject {
             try await AppStore.sync()
             await checkSubscriptionStatus()
         } catch {
-            print("Failed to restore purchases: \(error)")
+            AppLogger.iap.error("Failed to restore purchases: \(error.localizedDescription)")
         }
     }
 
@@ -162,7 +167,7 @@ class IAPManager: ObservableObject {
             let products = try await Product.products(for: productIdentifiers)
             availableProducts = products.filter { $0.type == .autoRenewable }
         } catch {
-            print("Failed to load products: \(error)")
+            AppLogger.iap.error("Failed to load products: \(error.localizedDescription)")
         }
     }