Add automatic rent notification feature to LocationEditForm

- Add rentDueNotification toggle to enable automatic rent notifications
- Add rentDueDay selector (1-28) for specifying when rent is due
- Extract tenant email to independent section shown when either autoBillFwd or rentDueNotification is enabled
- Update email validation to be mandatory when any automatic notification is active
- Update database schema to persist rentDueNotification and rentDueDay fields
- Add all database operations to handle new fields with proper defaults
- Add localization strings for English and Croatian

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

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

messages/en.json

@@ -134,11 +134,15 @@
     "auto-utility-bill-forwarding-legend": "AUTOMATIC UTILITY BILL FORWARDING",
     "auto-utility-bill-forwarding-info": "This option enables automatic forwarding of utility bills to the tenant via email according to the selected forwarding strategy.",
     "auto-utility-bill-forwarding-toggle-label": "forward utility bills",
-    "tenant-email-label": "Tenant Email",
-    "tenant-email-placeholder": "Enter tenant's email",
     "utility-bill-forwarding-strategy-label": "Forward utility bills when ...",
     "utility-bill-forwarding-when-payed": "all items are marked as paid",
     "utility-bill-forwarding-when-attached": "a bill (PDF) is attached to all items",
+    "auto-rent-notification-legend": "AUTOMATIC RENT NOTIFICATION",
+    "auto-rent-notification-info": "This option enables automatic sending of monthly rent bill to the tenant via email on the specified day of the month.",
+    "auto-rent-notification-toggle-label": "send rent notification",
+    "rent-due-day-label": "Day of month when rent is due",
+    "tenant-email-legend": "TENANT EMAIL",
+    "tenant-email-placeholder": "Enter tenant's email",
     "warning-missing-tenant-names": "Warning: Tenant first and last name are missing. The 2D barcode will not be displayed to the tenant when they open the shared link until both fields are filled in.",
     "save-button": "Save",
     "cancel-button": "Cancel",

messages/hr.json

@@ -133,11 +133,15 @@
     "auto-utility-bill-forwarding-legend": "AUTOMATSKO PROSLJEĐIVANJE REŽIJA",
     "auto-utility-bill-forwarding-info": "Ova opcija omogućuje automatsko prosljeđivanje režija podstanaru putem emaila u skladu s odabranom strategijom.",
     "auto-utility-bill-forwarding-toggle-label": "proslijedi režije automatski",
-    "tenant-email-label": "Email podstanara",
-    "tenant-email-placeholder": "Unesite email podstanara",
     "utility-bill-forwarding-strategy-label": "Režije proslijedi kada...",
     "utility-bill-forwarding-when-payed": "sve stavke označim kao plaćene",
     "utility-bill-forwarding-when-attached": "za sve stavke priložim račun (PDF)",
+    "auto-rent-notification-legend": "AUTOMATSKA OBAVIJEST O NAJAMNINI",
+    "auto-rent-notification-info": "Ova opcija omogućuje automatsko slanje mjesečnog računa za najamninu podstanaru putem emaila na zadani dan u mjesecu.",
+    "auto-rent-notification-toggle-label": "pošalji obavijest o najamnini",
+    "rent-due-day-label": "Dan u mjesecu kada dospijeva najamnina",
+    "tenant-email-legend": "EMAIL PODSTANARA",
+    "tenant-email-placeholder": "Unesite email podstanara",
     "warning-missing-tenant-names": "Upozorenje: Ime i prezime podstanara nedostaju. 2D barkod neće biti prikazan podstanaru kada otvori podijeljenu poveznicu dok oba polja ne budu popunjena.",
     "save-button": "Spremi",
     "cancel-button": "Odbaci",