Fix subscription screen: use product IDs and add close button

- Switch from groupID to productIDs for more reliable product loading
- Add dismiss button overlay so users aren't trapped if products fail to load
- Make productIdentifiers static for shared access

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Reflect/Localizable.xcstrings

@@ -3848,6 +3848,10 @@
         }
       }
     },
+    "Close" : {
+      "comment" : "An accessibility label for the button that dismisses the view.",
+      "isCommentAutoGenerated" : true
+    },
     "content_view_delete_entry" : {
       "extractionState" : "manual",
       "localizations" : {