feat(backend): 推荐商品接口支持分页(page/size)

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

cfc-backend/src/main/java/com/etotem/cfc/controller/recommendation/ProductRecommendationController.java

@@ -8,6 +8,7 @@ import lombok.extern.slf4j.Slf4j;
 import org.springframework.web.bind.annotation.*;
 
 import javax.annotation.Resource;
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 
@@ -43,8 +44,26 @@ public class ProductRecommendationController {
         Object limitObj = params.get("limit");
         int limit = limitObj != null ? toInt(limitObj) : 6;
 
-        List<Map<String, Object>> result = productRecommendationService.getDimensionRecommendations(
-                dimensionCode, familyId, memberId, excludeIds, limit, userId);
+        // 分页支持：page + size（不传 page 时保持原有 limit 行为，向后兼容）
+        Object pageObj = params.get("page");
+        int page = pageObj != null ? Math.max(1, toInt(pageObj)) : 1;
+        Object sizeObj = params.get("size");
+        int size = sizeObj != null ? Math.max(1, toInt(sizeObj)) : limit;
+
+        // 取全量候选（limit = page * size），再按页切片，保证翻页不重复、不遗漏
+        int fetchLimit = page * size;
+        List<Map<String, Object>> full = productRecommendationService.getDimensionRecommendations(
+                dimensionCode, familyId, memberId, excludeIds, fetchLimit, userId);
+
+        List<Map<String, Object>> result;
+        if (pageObj == null) {
+            // 未传 page：保持原有语义（取前 limit 条）
+            result = full.size() > limit ? full.subList(0, limit) : full;
+        } else {
+            int from = (page - 1) * size;
+            int to = Math.min(from + size, full.size());
+            result = from >= full.size() ? Collections.emptyList() : full.subList(from, to);
+        }
 
         return Result.success(result);
     }