chore: update document deletion logic to handle paragraph IDs and related mappings

--bug=1063248 --user=刘瑞斌 【知识库】删除文档时，分段与问题的关联关系没有清除 https://www.tapd.cn/62980211/s/1793500

Author: liuruibin

apps/knowledge/serializers/document.py

@@ -683,10 +683,11 @@ def delete(self):
             ]
             QuerySet(File).filter(id__in=source_file_ids).delete()
             QuerySet(File).filter(source_id=document_id, source_type=FileSourceType.DOCUMENT).delete()
+            paragraph_ids = QuerySet(model=Paragraph).filter(document_id=document_id).values_list("id", flat=True)
+            # 删除问题
+            delete_problems_and_mappings(paragraph_ids)
             # 删除段落
             QuerySet(model=Paragraph).filter(document_id=document_id).delete()
-            # 删除问题
-            delete_problems_and_mappings([document_id])
             # 删除向量库
             delete_embedding_by_document(document_id)
             QuerySet(model=DocumentTag).filter(document_id=document_id).delete()
@@ -1217,9 +1218,12 @@ def batch_delete(self, instance: Dict, with_valid=True):
                                Document.objects.filter(id__in=document_id_list).values("meta")]
             QuerySet(File).filter(id__in=source_file_ids).delete()
             QuerySet(Document).filter(id__in=document_id_list).delete()
-            QuerySet(Paragraph).filter(document_id__in=document_id_list).delete()
             QuerySet(DocumentTag).filter(document_id__in=document_id_list).delete()
-            delete_problems_and_mappings(document_id_list)
+            paragraph_ids = QuerySet(Paragraph).filter(document_id__in=document_id_list).values_list("id", flat=True)
+            # 删除问题关系
+            delete_problems_and_mappings(paragraph_ids)
+            # 删除段落
+            QuerySet(Paragraph).filter(document_id__in=document_id_list).delete()
             # 删除向量库
             delete_embedding_by_document_list(document_id_list)
             return True

apps/knowledge/sql/list_problem.sql

@@ -1,5 +1,6 @@
-SELECT
-		problem.*,
-		(SELECT "count"("id") FROM "problem_paragraph_mapping" WHERE problem_id="problem"."id") as "paragraph_count"
-	FROM
-		problem problem
+SELECT problem.*,
+       (SELECT COUNT(ppm.id)
+        FROM problem_paragraph_mapping ppm
+                 INNER JOIN paragraph p ON ppm.paragraph_id = p.id
+        WHERE ppm.problem_id = problem.id) AS "paragraph_count"
+FROM problem problem