refactor(templates): add error toast support to page templates

Update all page templates to accept an optional error message parameter
and display it via the ErrorToast component when data loading fails.

templates/devices.templ

@@ -2,7 +2,7 @@ package templates
 
 import "bookhoard/internal/handlers"
 
-templ Devices(user User, devices []handlers.DeviceInfo, pendingRegistrations []PendingRegistrationData, baseURL string) {
+templ Devices(user User, devices []handlers.DeviceInfo, pendingRegistrations []PendingRegistrationData, errorMessage string, baseURL string) {
 	<!DOCTYPE html>
 	<html lang="en">
 		<head>
@@ -863,6 +863,8 @@ templ Devices(user User, devices []handlers.DeviceInfo, pendingRegistrations []P
             // Load devices on page load
             loadDevices();
         </script>
+
+		@ErrorToast(errorMessage)
 		</body>
 	</html>
 }