fix: 修复 DataSourceController 泛型类型不匹配编译错误

backend/graph-service/src/main/java/com/lingyue/graph/controller/DataSourceController.java

@@ -52,7 +52,7 @@ public class DataSourceController {
      */
     @GetMapping("/{id}")
     @Operation(summary = "获取数据源", description = "根据ID获取数据源详情")
-    public AjaxResult<DataSource> getById(
+    public AjaxResult<?> getById(
             @PathVariable @Parameter(description = "数据源ID") String id) {
         
         DataSource dataSource = dataSourceService.getById(id);
@@ -104,7 +104,7 @@ public class DataSourceController {
      */
     @PutMapping("/{id}")
     @Operation(summary = "更新数据源", description = "更新数据源基本信息")
-    public AjaxResult<DataSource> update(
+    public AjaxResult<?> update(
             @PathVariable @Parameter(description = "数据源ID") String id,
             @RequestBody UpdateDataSourceRequest request) {
         
@@ -121,7 +121,7 @@ public class DataSourceController {
      */
     @PutMapping("/{id}/refs")
     @Operation(summary = "更新节点引用", description = "更新数据源绑定的节点引用（支持替换/追加/移除）")
-    public AjaxResult<DataSource> updateRefs(
+    public AjaxResult<?> updateRefs(
             @PathVariable @Parameter(description = "数据源ID") String id,
             @RequestBody UpdateRefsRequest request) {
         
@@ -138,7 +138,7 @@ public class DataSourceController {
      */
     @DeleteMapping("/{id}")
     @Operation(summary = "删除数据源", description = "删除指定数据源")
-    public AjaxResult<Void> delete(
+    public AjaxResult<?> delete(
             @PathVariable @Parameter(description = "数据源ID") String id) {
         
         dataSourceService.delete(id);
@@ -150,7 +150,7 @@ public class DataSourceController {
      */
     @GetMapping("/{id}/value")
     @Operation(summary = "获取数据源值", description = "从绑定的节点中提取并聚合值")
-    public AjaxResult<DataSourceValue> getValue(
+    public AjaxResult<?> getValue(
             @PathVariable @Parameter(description = "数据源ID") String id) {
         
         try {