fix(lastleg): preserve warehouse pallet business conflict responses

lastleg-service/src/main/java/com/baiyue/lastleg/inboundplan/pda/gateway/HttpWarehouseResourceGateway.java

@@ -179,15 +179,14 @@ public class HttpWarehouseResourceGateway implements WarehouseResourceGateway {
             .header("X-Internal-Service-Token", internalToken).retrieve()
             .onStatus(HttpStatusCode::isError, (request, result) -> { throw palletLookupFailure(result.getStatusCode()); })
             .body(WarehousePalletResponse.class);
-        if (response == null || response.data() == null) throw new ResponseStatusException(HttpStatus.SERVICE_UNAVAILABLE,
-            "Warehouse pallet service returned no usable response");
+        requirePalletResponse(response);
         return new WarehousePalletReference(response.data().id(), response.data().palletCode(), response.data().warehouseId(),
             response.data().locationId(), response.data().status(), response.data().fbaWarehouseCode(),
             response.data().unitPrice(), response.data().version());
     }
 
     private ResponseStatusException palletLookupFailure(HttpStatusCode status) {
-        return new ResponseStatusException(status.value() == 404 ? HttpStatus.NOT_FOUND
+        return new ResponseStatusException(status.value() == 409 ? HttpStatus.CONFLICT : status.value() == 404 ? HttpStatus.NOT_FOUND
             : (status.is4xxClientError() ? HttpStatus.BAD_REQUEST : HttpStatus.SERVICE_UNAVAILABLE),
             status.value() == 404 ? "Warehouse pallet was not found" : "Warehouse pallet lookup failed");
     }
@@ -199,14 +198,23 @@ public class HttpWarehouseResourceGateway implements WarehouseResourceGateway {
             .retrieve().onStatus(HttpStatusCode::isError, (request, result) -> {
                 throw palletLookupFailure(result.getStatusCode());
             }).body(WarehousePalletResponse.class);
+        requirePalletResponse(response);
+        return response;
+    }
+
+    /** 托盘状态冲突是业务拒绝，不能把HTTP 200内的A0409误报为仓储服务不可用。 */
+    private void requirePalletResponse(WarehousePalletResponse response) {
+        if (response != null && "A0409".equals(response.code())) {
+            throw new ResponseStatusException(HttpStatus.CONFLICT,
+                response.message() == null || response.message().isBlank() ? "Warehouse pallet state conflicts with this operation" : response.message());
+        }
         if (response != null && "A0404".equals(response.code())) {
             throw new ResponseStatusException(HttpStatus.NOT_FOUND, "Warehouse pallet was not found");
         }
-        if (response == null || response.data() == null) {
+        if (response == null || !"200".equals(response.code()) || response.data() == null) {
             throw new ResponseStatusException(HttpStatus.SERVICE_UNAVAILABLE,
                 "Warehouse pallet service returned no usable response");
         }
-        return response;
     }
 
     private WarehousePalletReference reference(WarehousePalletData pallet) {

lastleg-service/src/test/java/com/baiyue/lastleg/inboundplan/pda/gateway/HttpWarehouseResourceGatewayTest.java

@@ -164,6 +164,46 @@ class HttpWarehouseResourceGatewayTest {
         server.verify();
     }
 
+    /** 实际SHIP后报废的原托扫码仍拒绝；保留提供者业务码/原因，不伪装为服务故障或按ID重试。 */
+    @Test
+    void inspectPreservesScrappedPalletBusinessConflictWithoutFallback() {
+        server.expect(requestTo("http://warehouse/internal/v1/warehouse-pallets/resolve/D1747-1-001"))
+            .andRespond(withSuccess("""
+                {"code":"A0409","message":"托盘已报废","data":null}
+                """, MediaType.APPLICATION_JSON));
+        assertThatThrownBy(() -> gateway.inspectPallet("D1747-1-001"))
+            .isInstanceOfSatisfying(ResponseStatusException.class, error -> {
+                assertThat(error.getStatusCode()).isEqualTo(HttpStatus.CONFLICT);
+                assertThat(error.getReason()).isEqualTo("托盘已报废");
+            });
+        server.verify();
+    }
+
+    /** 按ID读取使用同一响应边界，错误码即使带data也不能被当作合法实托。 */
+    @Test
+    void idLookupRejectsBusinessConflictEvenWithPayload() {
+        server.expect(requestTo("http://warehouse/internal/v1/warehouse-pallets/resolve/id/31"))
+            .andRespond(withSuccess("""
+                {"code":"A0409","message":"托盘状态冲突","data":{"palletId":31,"palletCode":"PAL-1",
+                 "warehouseId":88,"locationId":40,"status":"IDLE","version":1}}
+                """, MediaType.APPLICATION_JSON));
+        assertThatThrownBy(() -> gateway.resolvePallet(31L))
+            .isInstanceOfSatisfying(ResponseStatusException.class, error ->
+                assertThat(error.getStatusCode()).isEqualTo(HttpStatus.CONFLICT));
+        server.verify();
+    }
+
+    /** 同一个状态冲突无论通过HTTP状态还是业务信封传输，都不能降为400或503。 */
+    @Test
+    void inspectPreservesHttpConflict() {
+        server.expect(requestTo("http://warehouse/internal/v1/warehouse-pallets/resolve/PAL-CONFLICT"))
+            .andRespond(withStatus(HttpStatus.CONFLICT));
+        assertThatThrownBy(() -> gateway.inspectPallet("PAL-CONFLICT"))
+            .isInstanceOfSatisfying(ResponseStatusException.class, error ->
+                assertThat(error.getStatusCode()).isEqualTo(HttpStatus.CONFLICT));
+        server.verify();
+    }
+
     @Test
     void resolveReservedFallsBackToConfirmedPhysicalBindingForEarlierPlanDisplayCode() {
         server.expect(requestTo("http://warehouse/internal/v1/warehouse-pallets/resolve/IP-ACY2-20260909-166786-P001"))