fix

app/Filament/Resources/ProjectResource.php

                     Tab::make('專案概要')->schema([
                         Select::make('region_id')->label('地區')->options(function () {
                             return Region::where('visible', true)->pluck('name', 'id');
-                        }),
+                        })->required(),
                         Translate::make()->schema(fn (string $locale) => [
                             Textarea::make('summaries')->label('簡述'),
                             TextInput::make('district')->label('區域'),