feat: add PostgreSQL web installation wizard

oa-backend/src/main/java/com/kaidi/oa/seed/LegalDemoSeeder.java

@@ -11,7 +11,6 @@ import com.kaidi.oa.repository.LegalCreditInvestRepository;
 import com.kaidi.oa.repository.LitigationCaseRepository;
 import org.springframework.boot.CommandLineRunner;
 import org.springframework.core.annotation.Order;
-import org.springframework.stereotype.Component;
 
 import java.time.Instant;
 
@@ -27,7 +26,7 @@ import java.time.Instant;
  * @Order(20) 在 DataSeeder(@Order 1) 之后运行；幂等（count>0 则跳过）。
  */
 @Order(20)
-@Component
+@DemoSeed
 public class LegalDemoSeeder implements CommandLineRunner {
 
     private final LitigationCaseRepository caseRepo;