Update Neon colors and show color circles in theme picker

- Update NeonMoodTint to use synthwave colors matching Neon voting style
  (cyan, lime, yellow, orange, magenta)
- Replace text label with 5 color circles in theme preview Colors row
- Remove unused textColor customization code and picker views
- Add .id(moodTint) to Month/Year views for color refresh
- Clean up various unused color-related code

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

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

Shared/IAPManager.swift

@@ -75,6 +75,12 @@ class IAPManager: ObservableObject {
 
     private var updateListenerTask: Task<Void, Error>?
 
+    /// Last time subscription status was checked (for throttling)
+    private var lastStatusCheckTime: Date?
+
+    /// Minimum interval between status checks (5 minutes)
+    private let statusCheckInterval: TimeInterval = 300
+
     // MARK: - Computed Properties
 
     var isSubscribed: Bool {
@@ -138,9 +144,21 @@ class IAPManager: ObservableObject {
     // MARK: - Public Methods
 
     /// Check subscription status - call on app launch and when becoming active
+    /// Throttled to avoid excessive StoreKit calls on rapid foreground transitions
     func checkSubscriptionStatus() async {
-        isLoading = true
-        defer { isLoading = false }
+        // Throttle: skip if we checked recently (unless state is unknown)
+        if state != .unknown,
+           let lastCheck = lastStatusCheckTime,
+           Date().timeIntervalSince(lastCheck) < statusCheckInterval {
+            return
+        }
+
+        // Only update isLoading if value actually changes to avoid unnecessary view updates
+        if !isLoading { isLoading = true }
+        defer {
+            if isLoading { isLoading = false }
+            lastStatusCheckTime = Date()
+        }
 
         // Fetch available products
         await loadProducts()