fix: pass self-reference in VendorTenantServiceTest for async proxy

The @Lazy self-proxy pattern requires a non-null reference in tests.
Construct the instance then re-create with itself as the self param.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/test/java/net/siegeln/cameleer/saas/vendor/VendorTenantServiceTest.java

@@ -79,10 +79,16 @@ class VendorTenantServiceTest {
             "jdbc:postgresql://pg:5432/db", "cameleer", "cameleer_dev",
             "jdbc:clickhouse://ch:8123/cameleer", "default", "cameleer_ch",
             "https://localhost/oidc", "http://cameleer-logto:3001/oidc/jwks", "https://localhost");
+        // Pass null for self-proxy initially, then re-create with the instance itself
+        // (in production, Spring's @Lazy proxy handles this circular ref)
         vendorTenantService = new VendorTenantService(
                 tenantService, tenantRepository, licenseService,
                 tenantProvisioner, serverApiClient, logtoClient, logtoConfig,
                 auditService, provisioningProps, dataCleanupService, tenantDatabaseService, null);
+        vendorTenantService = new VendorTenantService(
+                tenantService, tenantRepository, licenseService,
+                tenantProvisioner, serverApiClient, logtoClient, logtoConfig,
+                auditService, provisioningProps, dataCleanupService, tenantDatabaseService, vendorTenantService);
     }
 
     // --- Helpers ---