Add auto tenant notification toggle to LocationEditForm

Added toggle to control automatic tenant notifications with conditional
email field visibility based on the toggle state.

Changes:
- Added autoTenantNotification field to BillingLocation interface
- Updated LocationEditForm with "Notify tenant automatically" toggle
- Email field now only visible when autoTenantNotification is enabled
- Toggle appears after tenant name fields (when generateTenantCode is active)
- Updated updateOrAddLocation action to persist autoTenantNotification flag
- Added localization strings for toggle (Croatian/English)

Field visibility hierarchy:
1. Generate 2D code toggle (always visible)
2. Tenant name fields (visible when #1 is ON)
3. Auto notification toggle (visible when #1 is ON)
4. Email field (visible when #1 AND #3 are ON)

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

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

messages/hr.json

@@ -128,6 +128,7 @@
     "tenant-first-name-placeholder": "Unesite ime podstanara",
     "tenant-last-name-label": "Prezime podstanara",
     "tenant-last-name-placeholder": "Unesite prezime podstanara",
+    "auto-tenant-notification": "Automatski obavijesti podstanara",
     "tenant-email-label": "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.",