refactor: Improve tenant payment instructions UX and disable incomplete features

Renamed "2D CODE" feature to "PAYMENT INSTRUCTIONS" for better clarity
and disabled incomplete auto-forwarding features.

Changes:
- Renamed tenant 2D code section to "Payment Instructions"
- Updated labels to reflect that feature shows payment instructions + 2D code
- Added InfoBox with important note about required app settings (name & IBAN)
- Disabled auto bill forwarding toggle (feature incomplete)
- Disabled rent due notification toggle (feature incomplete)
- Updated translations in both English and Croatian

The new naming better reflects what the feature does: showing payment
instructions with IBAN details and a scannable 2D code to tenants.

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

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

app/ui/LocationEditForm.tsx

@@ -170,9 +170,10 @@ export const LocationEditForm: FC<LocationEditFormProps> = ({ location, yearMont
                                             ))}
                                     </div>
                                 </div>
+                                <InfoBox className="p-1 mb-1">{t("tenant-2d-code-note")}</InfoBox>  
                             </>
                         )}
-                    </fieldset>
+                </fieldset>
 
 
                     <fieldset className="fieldset bg-base-200 border-base-300 rounded-box w-xs border p-4 pb-2 mt-4">
@@ -182,6 +183,7 @@ export const LocationEditForm: FC<LocationEditFormProps> = ({ location, yearMont
                         <fieldset className="fieldset">
                             <label className="label cursor-pointer justify-start gap-3">
                                 <input
+                                    disabled={true}
                                     type="checkbox"
                                     name="autoBillFwd"
                                     className="toggle toggle-primary"
@@ -210,6 +212,7 @@ export const LocationEditForm: FC<LocationEditFormProps> = ({ location, yearMont
                         <fieldset className="fieldset">
                             <label className="label cursor-pointer justify-start gap-3">
                                 <input
+                                    disabled={true}
                                     type="checkbox"
                                     name="rentDueNotification"
                                     className="toggle toggle-primary"