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/SharingScreenshotExporter.swift

@@ -5,7 +5,6 @@
 //  Debug utility to export sharing template screenshots.
 //
 
-#if DEBUG
 import SwiftUI
 import UIKit
 
@@ -173,4 +172,3 @@ class SharingScreenshotExporter {
         return false
     }
 }
-#endif