Fix missing Japanese/Korean translations and BGTask string interpolation bug

Add "THE" translations for ja/ko in the subscription magazine header, and fix
broken string interpolation in BGTask error logging.

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

Shared/BGTask.swift

@@ -39,7 +39,7 @@ class BGTask {
         do {
             try BGTaskScheduler.shared.submit(request)
         } catch {
-            print("Could not schedule image fetch: (error)")
+            print("Could not schedule image fetch: \(error)")
         }
     }
 }