add bulk bill deletion across subsequent months

Implement ability to delete bills from all subsequent months
with toggle option and warning message similar to location deletion.
Includes centered warning box and efficient bulk operations.

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

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

messages/en.json

@@ -62,9 +62,12 @@
     }
   },
   "bill-delete-form": {
-    "text": "Please confirm deletion of bill “<strong>{bill_name}</strong>” at “<strong>{location_name}</strong>”.",
+    "text": "Please confirm deletion of bill \"<strong>{bill_name}</strong>\" at \"<strong>{location_name}</strong>\".",
     "cancel-button": "Cancel",
-    "confirm-button": "Confirm"
+    "confirm-button": "Confirm",
+    "delete-in-subsequent-months": "Also delete in all subsequent months",
+    "warning-title": "Warning",
+    "warning-message": "This operation cannot be undone and will delete the bill in all future months!"
   },
   "bill-edit-form": {
     "bill-name-placeholder": "Bill name",