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/hr.json

@@ -62,9 +62,12 @@
     }
   },
   "bill-delete-form": {
-    "text": "Molim potvrdi brisanje računa “<strong>{bill_name}</strong>” koji pripada nekretnini “<strong>{location_name}</strong>”.",
+    "text": "Molim potvrdi brisanje računa \"<strong>{bill_name}</strong>\" koji pripada nekretnini \"<strong>{location_name}</strong>\".",
     "cancel-button": "Odustani",
-    "confirm-button": "Potvrdi"
+    "confirm-button": "Potvrdi",
+    "delete-in-subsequent-months": "Također obriši i u svim mjesecima koji slijede",
+    "warning-title": "Upozorenje",
+    "warning-message": "Ova operacija je nepovratna i obrisat će račun u svim mjesecima koji slijede!"
   },
   "bill-edit-form": {
     "bill-name-placeholder": "Ime računa",