Remove #if DEBUG guards for TestFlight, polish weekly digest and insights UX

- Remove #if DEBUG from all debug settings, exporters, and IAP bypass so
  debug options are available in TestFlight builds
- Weekly digest card: replace dismiss X with collapsible chevron caret
- Weekly digest: generate on-demand when opening Insights tab if no cached
  digest exists (BGTask + notification kept as bonus path)
- Fix digest intention text color (was .secondary, now uses theme textColor)
- Add "Generate Weekly Digest" debug button in Settings
- Add generating overlay on Insights tab with pulsing sparkles icon that
  stays visible until all sections finish loading (content at 0.2 opacity)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Shared/Services/ExportableInsightsViews.swift

@@ -4,8 +4,6 @@
 //
 //  Exportable insights views with sample AI-generated insights for screenshots.
 //
-
-#if DEBUG
 import SwiftUI
 
 // MARK: - Sample Insights Data
@@ -377,4 +375,3 @@ struct ExportableInsightsContainer<Content: View>: View {
             .background(backgroundColor)
     }
 }
-#endif