修复V3空业务根回调处理

server/src/test/java/cn/nianxx/thhotel/workflows/reservation/control/SuperAgentTaskResultControllerTest.java

@@ -805,6 +805,38 @@ class SuperAgentTaskResultControllerTest {
         assertThat(transitionCount).isEqualTo(1L);
     }
 
+    @Test
+    void shouldRejectEmptyV3BusinessRootWithoutPersistingBatch() throws Exception {
+        SourceMessageCaptureResult source = captureSourceMessage("mail-v3-empty-business-root-001");
+        String body = """
+                {
+                  "source_message": {
+                    "source_message_id": "mail-v3-empty-business-root-001",
+                    "subject": "Empty business root",
+                    "from": null,
+                    "cc": [],
+                    "received_at": null,
+                    "source_channel": "Email"
+                  },
+                  "message_events": [],
+                  "case_candidates": [],
+                  "extraction_warnings": [],
+                  "unhandled_current_intents": []
+                }
+                """;
+
+        mockMvc.perform(signedPost(body, "nonce-v3-empty-business-root-001"))
+                .andExpect(status().isBadRequest())
+                .andExpect(jsonPath("$.error_code").value("TASK_RESULTS_EMPTY"));
+
+        Long batchCount = jdbcTemplate.queryForObject("""
+                SELECT COUNT(*)
+                FROM workflow_reservation_ai_batch
+                WHERE source_message_id = ?
+                """, Long.class, source.inboxId());
+        assertThat(batchCount).isZero();
+    }
+
     @Test
     void shouldPersistAdapterContractErrorWhenV3EventRouteCannotBeDerived() throws Exception {
         SourceMessageCaptureResult source = captureSourceMessage("mail-v3-adapter-error-001");